If you have mosquitoes at home, first clear breeding sources such as standing water and the building's sewage pit and septic tank, install window screens and door-gap barriers, and then apply repellent as needed. The Taiwan CDC recommends: adults should choose DEET at a concentration of 50% or less; children 2 months and older, only DEET at 10%-30%; picaridin (派卡瑞丁) and IR3535 (伊默克) are suitable only for age 2 and above under current product licenses; infants under 2 months should not use repellent and should wear light-colored long sleeves and long pants and use a mosquito net instead. The TFDA, for its part, reminds that mosquito repellent products should not be used on infants under 6 months; follow the product's package insert (仿單) in practice. The Taiwan CDC also explains that the concentration of DEET, picaridin, or IR3535 has no direct relationship to effectiveness; it affects how long the protection lasts, and a higher concentration usually protects longer.
Reminder: The two agencies word it differently for infants, and this article lists them separately without merging them. The Taiwan CDC dengue Q&A says children 2 months and older can use DEET at 10%-30%. The TFDA press release of July 2017, which announced that single-ingredient DEET repellent drugs at 15% or less were reclassified as class B over-the-counter drugs (乙類成藥), on the other hand reminds that when used for children, infants under 6 months should not use it. Each product's package insert may also set its own age limits, so rely on the product license and package insert; for infants and young children, you can first ask a doctor or pharmacist. This article focuses on home mosquito protection; for inspecting water-holding containers, penalties, and seeing a doctor for fever, see Household water-holding container inspection checklist.
Mosquitoes that bite in your room at night are mostly house mosquitoes
In 2017, the Taiwan CDC invited Professor 杜武俊 of the entomology department at Chung Hsing University (中興大學) to explain that the mosquitoes commonly found in communities include, besides the Egyptian Aedes mosquito and the white-striped Aedes mosquito, the tropical house mosquito, the underground house mosquito (地下家蚊), and the white-bellied bush mosquito, which bite at different times of day:
| Mosquito species | Main biting time | Breeding or resting places | Situation in Taipei and New Taipei |
|---|
| Tropical house mosquito (熱帶家蚊) | At night, especially after lights out for sleep (national museum of natural science) | Ditches, puddles, septic tanks, and similar places (national museum of natural science) | The national museum of natural science says it is the most common mosquito in Taiwan's urban homes and the main biting species indoors |
| White-striped Aedes mosquito (白線斑蚊) | Daytime, with two peaks a day at dawn and dusk (Taiwan CDC) | Mostly rests outdoors, in potted plants, clutter, tire piles, grass and bamboo thickets, and empty houses near breeding sources (Taiwan CDC) | Taiwan CDC: found across the lowlands of Taiwan and in mountain areas below 1,500 meters, including Taipei and New Taipei |
| Egyptian Aedes mosquito (埃及斑蚊) | Daytime, with a peak at 4-5 p.m. and a secondary peak at 9-10 a.m. (Taiwan CDC) | Immature stages live in water-holding containers indoors and outdoors, basement standing water, and discarded tires (Chemicals Administration); likes to rest in dark, damp indoor corners (Taiwan CDC) | Taiwan CDC: found in the counties and cities south of Budai (布袋), Chiayi |
| White-bellied bush mosquito (白腹叢蚊) | Dusk (Taiwan CDC press release) | This article found no official information | - |
Indoors, mosquitoes like to hide in dark corners, under or behind furniture, behind curtains and drapes, and in basements (Taiwan CDC press release). Living on a high floor is no guarantee either: the Taiwan CDC explains that mosquitoes ride elevators when the doors open, or rise with air currents, so watch for standing water downstairs, in the basement, or in the parking garage.
Cut off breeding sources first: your home and the whole building
The Taiwan CDC points out that after taking blood, mosquitoes look for water to lay eggs in, and larvae and pupae live in water, so not creating standing water is the most fundamental method; sewage pits and septic tanks in building basements also need good management. Compiled from the Taiwan CDC press release and the Taipei City Department of Environmental Protection handbook:
- Inside the home: Clear water-holding containers such as flowerpot saucers, the water tray under the refrigerator, and water storage buckets (breeding sources listed by the Taiwan CDC). The Taiwan CDC press release suggests putting a sponge, mesh, or absorbent material at the bottom of indoor potted plants to keep mosquitoes from laying eggs. For the full list of containers and the "patrol, empty, clear, scrub" method, see this site's water-holding container inspection checklist.
- Barriers: Install screen doors, window screens, and door-gap barriers (Taiwan CDC press release). For how to replace torn screen mesh, see DIY window screen replacement.
- Building septic tanks and sewage pits: The Taipei City Department of Environmental Protection's handbook on environmental hygiene management for community buildings (《社區大廈環境衛生管理手冊》, December 2016) points out that septic tanks and sewage pits contain high concentrations of organic matter that suit mosquito breeding, and recommends regularly checking in the basement that the covers are sealed. If there are openings, seal the outlets that are not needed and fit mesh on the remaining ones; drainage ditches can also be fitted with mesh. If a tank has not been cleaned for more than 1 year, cleaning should be arranged promptly. For Taipei septic tank cleaning declarations, the handbook lists the inquiry line as 1999 ext. 7261 (data from the 2016 edition; follow the latest announcement of the Department of Environmental Protection).
This article's suggestion: if you live in an apartment building and mosquitoes are especially bad at night, you can ask the management committee (管委會) or the property management company to check the basement sewage pit, the septic tank covers, and the mesh; these are breeding sources that individual residents cannot clean themselves.
Choosing a repellent: ingredient, concentration, age
The Taiwan CDC explains that government-approved skin repellents fall into three types by ingredient, and all of them work effectively:
| Ingredient | Adults | Children | Infants |
|---|
| DEET (待乙妥 / 敵避) | Concentration of 50% or less | From 2 months, only 10%-30% is recommended; wash it off thoroughly after coming indoors | Not suitable under 2 months |
| Picaridin (派卡瑞丁) | Follow the product label | Under current licenses, only suitable for age 2 and above | Not suitable |
| IR3535 (伊默克) | Follow the product label | Under current licenses, only suitable for age 2 and above | Not suitable |
The table follows the "mosquito protection" section of the Taiwan CDC dengue Q&A (that item was last updated on February 9, 2021). In addition, a 2017 TFDA press release explains that after single-ingredient DEET repellent drugs at 15% or less were reclassified as class B over-the-counter drugs, convenience stores and department and variety stores can sell them in addition to pharmacies, and reminds that infants under 6 months should not use them; the same ingredient may carry different package insert limits in different products.
You can tell whether a product can go on skin from the license number on the packaging (Taiwan CDC Q&A, last updated June 24, 2024):
- Approved by the Ministry of Health and Welfare: DEET repellents printed with numbers such as 衛部（署）藥製字 or 衛部（內衛）成製字 can be applied or sprayed directly on skin.
- Approved by the Ministry of Environment: Printed with 環部（署）衛製字 or 環部（署）衛輸字. Some of these are approved only for use on the environment (such as window screens, screen doors, and tents), so check whether the instructions say "may be used on exposed human skin" (得使用於人體裸露之皮膚) or "this product must not be sprayed on skin or clothing" (本產品不可噴灑於皮膚或衣物上). Picaridin and IR3535 repellents approved by the Ministry of Environment can be used directly on skin.
- The Chemicals Administration, Ministry of Environment explains that DEET products used on skin are called 待乙妥 as human medicine, while those used in indoor and outdoor environments are environmental hygiene pesticides called 敵避. Environmental pesticide license numbers can be looked up in the online query system for environmental pesticide licenses and vector control operators.
For natural or plant-extract repellents, the Taiwan CDC "vector-borne disease prevention" page (last updated October 1, 2012) says their effectiveness cannot be compared with DEET and the protection time is usually short, from a few minutes to 2 hours.
How to apply repellent safely
Compiled from the 2017 TFDA press release and the Taiwan CDC Q&A:
- Read the package insert (仿單) carefully before use.
- Spray 10-15 cm from the skin or clothing, slowly; repellent forms protection only when applied to exposed skin.
- For the face, spray onto your palm first and then apply; avoid the areas around the eyes and mouth; do not use it on wounds, or on allergic or sunburned skin.
- For children, an adult sprays onto their own palm first and then applies it; the Taiwan CDC "vector-borne disease prevention" page also reminds you to avoid applying it on children's hands, so it does not get into the eyes, nose, or mouth or get swallowed.
- When you also need sunscreen, apply sunscreen first and use repellent after an interval of 5-10 minutes (TFDA). The Taiwan CDC "vector-borne disease prevention" page (2012) says 15 minutes, and does not recommend choosing sunscreen-repellent combination products, to avoid an excess of repellent ingredient.
- Reapply when you sweat a lot or when you notice mosquitoes circling around you again (Taiwan CDC); wash it off with soap once you are back indoors.
- If it gets in the eyes, rinse immediately with plenty of water for 10-15 minutes; if your skin feels unwell, stop using it and consult a doctor or pharmacist (TFDA).
Mosquito-catching devices, mosquito coils and electric repellents, insecticide sprays
Mosquito-catching devices: A 2017 Taiwan CDC press release suggests placing mosquito-catching devices at places mosquitoes prefer to rest. In Professor 杜武俊's community egg-trap bucket (誘卵桶) experiment, buckets were placed on the ground and at 50, 100, and 150 cm above the ground, with positive rates of 24%, 35%, 29%, and 20% respectively. The highest was at 50 cm above the ground, so you can choose a suitable position and height for your environment; it need not be on the ground. This article's suggestion: bug zappers and mosquito traps can reduce only some adult mosquitoes and cannot replace clearing breeding sources and installing window screens.
Mosquito coils and electric mosquito repellents: The Chemicals Administration reminds that homes with elderly people, young children, or people with respiratory illness should use them less; watch for flammable items around mosquito coils; do not let children touch the heating plate of an electric mosquito repellent.
Insecticide sprays: The Chemicals Administration's precautions are: before spraying, move people and animals out, and cover tableware and fish tanks; wear long sleeves and spray while backing out, from the inside toward the outside; after spraying, close doors and windows tightly and wash your hands and rinse your mouth, and after 30 minutes open the windows for ventilation and sweep up the dead insects; do not spray at fire, people, food, or frequently touched places; children should not do the spraying. The Chemicals Administration also explains that synthetic pyrethroid agents are highly toxic to fish, so if you keep fish, cover the tank tightly and turn off the aeration equipment. Before buying, likewise check the Ministry of Environment license number; for the format, see the article on cockroach pesticides.
Ordering overseas mosquito-repellent patches and repellents online: The Chemicals Administration explains that a product whose packaging has no number such as 環部／環署衛製字, 衛輸字, or 環衛藥防蟲字 is a counterfeit drug (偽藥), and importing counterfeit drugs can be fined NT$300,000 to NT$1,500,000 under the law; travelers may carry 1 kg or less for personal use, but may not sell it. Article 32 of the environmental-use pesticide management law (環境用藥管理法) provides that those without a permit or license may not advertise environmental-use pesticides, and violators are fined NT$60,000 to NT$300,000 under Article 48.
Taipei and New Taipei: how to find whole-building disinfection or report a problem
- If a community wants to hire a company to spray, the Taipei City Department of Environmental Protection handbook reminds that a cleaning company is not a disinfection and pest control company; look for a company that holds a vector control operator permit license, which should submit a work plan before the job for the community to sign, post a notice larger than A4, and after spraying, it is advised to stay out for at least 2 hours.
- To check for legitimate companies: the Chemicals Administration's vector control operator permit license query can be filtered by issuing authority, "Taipei City Government" or "New Taipei City Government". The New Taipei City Environmental Protection Department has published its lists of top-rated vector control operators for the 2023 and 2024 evaluations, and the open data platform also has a yearly updated list of New Taipei operators.
- Epidemic and medical consultation: Taiwan CDC epidemic prevention hotline 1922 (or 0800-001922).
FAQ
Can repellent be used on infants?
The Taiwan CDC explains that repellents containing DEET, picaridin, or IR3535 are not suitable for infants under 2 months, and recommends light-colored long sleeves and long pants and a mosquito net; from 2 months, only DEET at 10%-30% is recommended, and picaridin and IR3535 are limited to age 2 and above under current licenses. A 2017 TFDA press release, for its part, reminds that when mosquito repellent products are used for children, infants under 6 months should not use them. The two agencies word it differently, so follow the product's package insert, and ask a doctor or pharmacist if unsure.
Is a higher DEET concentration more effective?
The Taiwan CDC explains that the concentration of DEET, picaridin, or IR3535 has no direct relationship to potency but relates to duration, and a higher concentration usually protects longer. For adults, 50% or less is recommended; reapply if you sweat a lot or mosquitoes come close again.
Why are there still mosquitoes on the 10th floor or above?
The Taiwan CDC explains that the chance of mosquitoes flying directly from the ground up to the 10th floor is small, but they enter when elevator doors open or rise with air currents. Check for standing water downstairs, in the basement, and in the parking garage, and whether the covers of the building's sewage pit and septic tank are sealed and fitted with mesh.
Can a repellent made for the environment be sprayed on the body?
It depends on the instructions. The Taiwan CDC explains that some repellents approved by the Ministry of Environment are approved only for use on the environment, and their instructions state "this product must not be sprayed on skin or clothing"; those that can go on skin state "may be used on exposed human skin". DEET products carrying a Ministry of Health and Welfare number (藥製字, 成製字) can be used directly on skin.
What if I get a fever after a mosquito bite?
The Taiwan CDC reminds that if symptoms such as fever, joint and bone pain, pain behind the eyes, or a rash appear, seek medical care promptly and proactively tell the doctor your travel history. Epidemic prevention hotline: 1922. For inspecting standing water at home and precautions during the epidemic season, see this site's water-holding container inspection checklist.
Last updated: 2026-11-03
This article was compiled by SOSfix editors from public information and is for general reference only. For your own case, contact the Taiwan CDC, Ministry of Health and Welfare (epidemic prevention hotline 1922), or your local health bureau or environmental protection bureau; for medication questions, consult a doctor or pharmacist.
Sources
- Taiwan CDC, Ministry of Health and Welfare: dengue Q&A, mosquito protection section (each item last updated between 2019/1/7 and 2024/6/24, verified 2026-11-02) (in Chinese): the three types of repellent ingredients, adult DEET at 50% or less, 10%-30% from 2 months, not suitable under 2 months, picaridin and IR3535 limited to age 2 and above by license, concentration versus duration, when to reapply, differences between Ministry of Health and Welfare and Ministry of Environment numbers and package notes, Aedes species distribution and biting times, mosquitoes on the 10th floor, seeking care for fever and travel history.
- Ministry of Health and Welfare (source: Taiwan Food and Drug Administration): repellent reclassified as a "class B over-the-counter drug" for easier purchase and correct use (filed 2017-07-04, verified 2026-11-02) (in Chinese): reclassification of single-ingredient preparations at DEET 15% or less as class B over-the-counter drugs and the sales channels, spraying from 10-15 cm, spraying the palm first for the face, no use on wounds, allergic, or sunburned skin, sunscreen first with a 5-10 minute gap, adults applying for children, not for infants under 6 months, rinsing for 10-15 minutes if it gets in the eyes.
- Taiwan CDC, Ministry of Health and Welfare: vector-borne disease prevention (last updated 2012/10/1, verified 2026-11-02) (in Chinese): avoiding application on children's hands, a 15-minute gap after sunscreen and not recommending combination products, natural-ingredient repellents lasting from a few minutes to 2 hours (an old page; the agency name on it is still 環保署).
- Taiwan CDC, Ministry of Health and Welfare: DIY home mosquito protection, with the entomology department of Chung Hsing University introducing mosquito-catching devices (published 2017-05-23, verified 2026-11-02) (in Chinese): common mosquito species and biting times, indoor resting places, not creating standing water, managing basement sewage pits and septic tanks, screen doors, window screens and door-gap barriers, sponge or mesh in pot bottoms, mosquito-catching devices, egg-trap bucket heights and positive rates of 24%/35%/29%/20%, epidemic prevention hotline 1922.
- National museum of natural science (國立自然科學博物館), "Let's explore the insects in your home": tropical house mosquito (verified 2026-11-02; the page shows no date) (in Chinese): hides in dark places indoors by day and bites at night, prefers to lay eggs in ditches, puddles, and septic tanks, the main biting mosquito indoors in Taiwan and the most common in urban homes, mosquito nets, window screens, and repellent.
- Chemicals Administration, Ministry of Environment, environmental pesticide safe-use education site: choose repellent carefully for it to work (published 2019-10-24, verified 2026-11-02) (in Chinese): DEET is called 待乙妥 for human use and 敵避 for environmental use, the format of legitimate license numbers, personal-use carrying by travelers is not for sale.
- Chemicals Administration, Ministry of Environment, environmental pesticide safe-use education site: mailing in imported mosquito-repellent patches may be illegal importation of counterfeit drugs (published 2019-10-24, verified 2026-11-02) (in Chinese): no license number means a counterfeit drug, importing counterfeit drugs is fined NT$300,000 to NT$1,500,000, carrying 1 kg or less is limited to personal use and may not be sold.
- Chemicals Administration, Ministry of Environment, environmental pesticide safe-use education site: dengue vector mosquito control drugs are low in toxicity, safe, and effective (published 2023-10-02, verified 2026-11-02) (in Chinese): synthetic pyrethroids are highly toxic to fish, cover fish tanks tightly and turn off aeration before spraying, precautions before and after spraying.
- Taiwan CDC, Ministry of Health and Welfare: how to use disinfectants and eliminate mosquito breeding sources (published 2001-08-02, verified 2026-11-02) (in Chinese): examples of breeding sources such as basement standing water, rooftop standing water, plastic water storage buckets, trays under refrigerators, and flowerpot saucers; scrubbing the inner walls of containers.
- Chemicals Administration, Ministry of Environment, environmental pesticide safe-use education site: mosquito ecology and control (published 2019-10-21, verified 2026-11-02) (in Chinese): the immature stages of the Egyptian Aedes mosquito live in water-holding containers indoors and outdoors, basement standing water, and discarded tires; only female mosquitoes bite.
- Chemicals Administration, Ministry of Environment, environmental pesticide safe-use education site: how to use environmental pesticides (published 2019-10-21, verified 2026-11-02) (in Chinese): who each application method suits, precautions for insecticide sprays (move people and animals out, cover tableware and fish tanks, close doors and windows after spraying and ventilate after 30 minutes, do not spray at fire, people, or food, children should not spray), precautions for mosquito coils and electric mosquito repellents.
- Chemicals Administration, Ministry of Environment: online query system for environmental pesticide licenses and vector control operators (verified 2026-11-02) (in Chinese): look up environmental pesticide licenses, vector control operator permit licenses, and sales business permit licenses; customer service (02)2314-0266 ext. 9.
- National laws and regulations database (全國法規資料庫): environmental-use pesticide management law (amended December 7, 2016, verified 2026-11-02) (in Chinese): Article 5 definition of vector control operators, Article 9 environmental pesticides must be inspected and registered and announced online, Article 11 vector control operators need a permit license to operate and are announced online, Article 21 restrictions on users of special environmental pesticides, Article 32 no advertising without a license, Articles 46 and 48 fines.
- Taipei City Department of Environmental Protection: handbook on environmental hygiene management for community buildings (compiled December 2016, PDF, verified 2026-11-02) (in Chinese): a cleaning company is not a disinfection and pest control company, markings on operators' vehicles and staff clothing, the content and signature of the work plan, a notice larger than A4, dedicated staff on site to supervise, avoiding entry for at least 2 hours after spraying; septic tank and sewage pit covers sealed and fitted with mesh, cleaning to be arranged if not cleaned for more than 1 year, septic tank inquiry line 1999 ext. 7261.
- Chemicals Administration, Ministry of Environment: vector control operator permit license query (verified 2026-11-02) (in Chinese): searchable by permit license number, issuing authority (including Taipei City Government and New Taipei City Government), person in charge, and company name.
- New Taipei City Environmental Protection Department: evaluation of vector control operators (verified 2026-11-02) (in Chinese): New Taipei has held evaluations of vector control operators since 2022, published the top-rated lists for 2023 and 2024, and says to commission qualified operators, who can be looked up in the Chemicals Administration query system.
- New Taipei City open data platform: list of New Taipei vector control operators (verified 2026-11-02) (in Chinese): fields include company name, license number, and address; updated yearly; the providing agency's phone is (02)2953-2111 ext. 3253.
