The label is the law. Read your product's label before you mix or apply; the rates here come from the labels listed under Sources.
- Active ingredient
- Fipronil (CAS 120068-37-3)
- Chemical class
- Phenylpyrazole insecticide.[1]
- Mode of action
- IRAC Group 2B: GABA-gated chloride channel blockers: phenylpyrazoles (fiproles)[4]
- Signal words
- Nouvel Sales Fipronil Roach Bait Gel (also sold as TERRO Roach Killing Gel Baits): Caution[2]
Termidor SC Termiticide/Insecticide: Caution[3]
How it works
Fipronil kills insects that eat or touch it by disrupting their central nervous system, and it is more toxic to insects than to people and pets because it binds more readily to insect nerve endings.[1]
It is in IRAC Group 2B; pyrethroid sprays are Group 3A, so a fipronil bait is a different mode of action for cockroaches that have stopped responding to sprays.[4]
Placing gel bait
Put bait close to where cockroaches hide, travel and feed: corners, cracks and crevices, under sinks and baseboards, and around water pipes and water heaters.[2]
Inspect the placements and add bait when it has been eaten; the label says to expect fewer German cockroaches within a day and fewer American cockroaches in three to four days.[2]
Outdoors next to the house, place bait at entry points such as eaves, sills and expansion joints, in protected spots, because direct sun and water shorten how long it stays effective.[2]
Termite treatment is a job for a licensed company
Termidor SC soil treatments are mixed at 0.06%, 0.09% or 0.125% and applied by trenching and rodding along foundations, under rules a homeowner is not licensed to follow.[3]
In soil, half of the fipronil breaks down in about 125 days; it binds tightly to soil and is not expected to reach groundwater.[1]
Where it is used
The gel is a spot or crack-and-crevice bait for cockroaches inside homes and outdoors next to the structure, kept off food-preparation surfaces and away from foods.[2]
Do not put gel where insecticide was recently sprayed, and do not spray over the bait, because sprays can make it less attractive.[2]
Termidor SC may be sold to, used and stored only by individuals or firms licensed or registered by the state to apply termiticides or general pest control products.[3]
Products and registrations
| Product | Registrant | EPA Reg. No. | Active % | Formulation | Signal word |
|---|---|---|---|---|---|
| Nouvel Sales Fipronil Roach Bait Gel (also sold as TERRO Roach Killing Gel Baits)[2] | Nouvel Sales, LLC | 92028-4 | 0.05% | ready-to-use gel bait | Caution |
| Termidor SC Termiticide/Insecticide[3] | BASF Agricultural Solutions US, LLC | 7969-210 | 9.1% | suspension concentrate | Caution |
Label rates
| Product | Use | Pests | Rate |
|---|---|---|---|
| Nouvel Sales Fipronil Roach Bait Gel (also sold as TERRO Roach Killing Gel Baits) | Indoors and next to the house: German and brownbanded cockroaches | German and brownbanded cockroaches | 0.75–3.0 g per sq yd[2] 0.75 g per square yard for ongoing maintenance, up to 1.5 g for light to moderate infestations, up to 3.0 g to clean out a heavy one. On the label's scale, 0.1 g is a quarter-inch spot and 1.0 g a dime-size spot; many small spots work faster than a few big ones. |
| Nouvel Sales Fipronil Roach Bait Gel (also sold as TERRO Roach Killing Gel Baits) | Indoors and next to the house: large cockroaches | American, smokybrown and oriental cockroaches | 1.0–2.0 g per sq yd[2] |
How to apply it, step by step
1. Protective gear
- Avoid contact with skin, eyes and clothing, and wash with soap and water after handling and before eating, drinking, smoking or using the toilet; it is harmful if absorbed through skin.[2]
2. Before you spray
- Place it only where children and pets can't easily reach it, never on food-preparation surfaces, and away from foods and food-contact surfaces.[2]
- Don't put gel where you've recently sprayed insecticide, and don't spray over the gel later: sprays can make the bait repellent.[2]
- Skip spots that get washed routinely, surfaces hotter than 130°F such as parts of stoves, toasters, dishwashers and hot water pipes, and places in direct sunlight; the gel can stain fabrics and porous surfaces.[2]
3. Mixing
- Nothing to mix: it's a ready-to-use gel applied from the syringe.[2]
4. Applying
- Apply small spots about ¼ inch across, or thin beads, into cracks and crevices and near where roaches hide and feed: corners, openings into wall and floor voids, around pipes, doors and windows, and behind and under appliances and cabinets.[2]
- For light to moderate infestations, place 1 to 3 spots per 10 linear feet or square yard; for heavy infestations, 3 to 5. Many small placements work faster than a few large ones.[2]
- Outdoors, it can go at entry points such as along windows and doors, utility openings and garbage areas, placed where people are unlikely to touch it.[2]
5. After you spray
- If gel lands on an exposed surface, wipe it off with a damp paper towel (or scrape off dried gel with a putty knife), wash the surface, and put the residue in the trash.[2]
First aid
- On skin or clothing, take off contaminated clothing and rinse skin with plenty of water for 15 to 20 minutes; in the eyes, hold them open and rinse gently for 15 to 20 minutes, removing contact lenses after the first 5 minutes.[2]
- For a medical emergency, call poison control at 1-800-222-1222; for general product questions, the National Pesticide Information Center at 1-800-858-7378.[2]
Storage, spills and disposal
- Store it in a cool, dry place out of children's reach.[2]
- Put an empty syringe in the trash or recycling; for a partly used one, call your local solid waste agency or 1-800-CLEANUP, and never put unused product down a drain.[2]
From the safety data sheet
- The SDS uses the label signal word Caution and says the gel, a brown paste, isn't expected to cause immediate effects from short-term exposure; it doesn't meet OSHA's definition of a hazardous chemical.[5]
- If gel gets in the eyes, hold the eye open and rinse slowly and gently with water for 15 to 20 minutes, taking out contact lenses after the first 5 minutes, then call a poison control center or doctor for advice.[5]
- On skin, take off contaminated clothing and rinse the skin right away with plenty of water for 15 to 20 minutes, then call a poison control center or doctor for advice.[5]
- If someone swallows it, call a poison control center or doctor right away; have the person sip a glass of water if able to swallow, and don't induce vomiting unless the poison center or doctor says to.[5]
- The SDS lists restlessness, anxiety and tremors as the main symptoms of overexposure, and warns that the gel stains porous surfaces.[5]
Safety and environmental hazards
People
The gel label signal word is CAUTION: harmful if absorbed through skin and causes moderate eye irritation. People who swallowed fipronil reported sweating, nausea, vomiting, headache, dizziness and seizures, and EPA classifies fipronil as a possible human carcinogen based on thyroid tumors in rats fed the highest dose.[2][1]
Pets
The gel label says to use it only where children and pets cannot easily reach it and to place bait out of reach of pets. Fipronil is also the active ingredient in many pet flea and tick spot-ons, where skin contact during application is the main exposure for owners.[2][1]
Bees and pollinators
NPIC reports that fipronil is highly toxic to honey bees but not toxic to earthworms.[1]
Fish and water
Fipronil is highly toxic to freshwater and marine fish and invertebrates, and two of its breakdown products were more toxic than fipronil itself; the Termidor label says it is toxic to birds, fish and aquatic invertebrates.[1][3]
Common questions
- Can I buy Termidor and treat my own house for termites?
- No. The Termidor SC label restricts sale, use and storage to people or firms licensed or registered by the state to apply termiticides or general pest control products.[3]
- How much roach gel should I use?
- The fipronil gel label calls for 0.75 to 3.0 grams per square yard for German and brownbanded cockroaches depending on how bad the infestation is, and 1 to 2 grams per square yard for larger cockroaches. A dime-size spot is about 1 gram.[2]
- Is fipronil a carcinogen?
- EPA classifies fipronil as a possible human carcinogen, based on thyroid tumors in rats fed the highest dose; scientists have not found evidence that it causes cancer in people.[1]
- Is fipronil dangerous to fish?
- Yes. It is highly toxic to fish and aquatic invertebrates, and some breakdown products are more toxic still.[1]
Sources
- National Pesticide Information Center, “Fipronil General Fact Sheet.” npic.orst.edu/factsheets/fipronil.html (accessed 2026-10-06)
- U.S. EPA Pesticide Product Label System, “Nouvel Sales Fipronil Roach Bait Gel label, EPA Reg. No. 92028-4 (EPA-stamped, June 26, 2026).” www3.epa.gov/pesticides/chem_search/ppls/092028-00004-20260626.pdf (accessed 2026-10-06)
- U.S. EPA Pesticide Product Label System, “Termidor SC Termiticide/Insecticide label, EPA Reg. No. 7969-210 (EPA-stamped, Apr. 30, 2024).” www3.epa.gov/pesticides/chem_search/ppls/007969-00210-20240430.pdf (accessed 2026-10-06)
- Insecticide Resistance Action Committee, “IRAC Mode of Action Classification Scheme, Version 11.5 (Feb. 2026).” irac-online.org/documents/moa-classification/ (accessed 2026-10-06)
- Mylva S.A. (distributor), “Ultimatum Pest Roach Gel Bait Safety Data Sheet (Mylva S.A., revision March 2022; EPA Reg. No. 92028-4, the same registration as the page's Nouvel Sales Fipronil Roach Bait Gel, sold under another brand name; copy hosted on labelsds.com).” labelsds.com/images/user_uploads/Ultimatum%20Pest%20SDS%203-1-22.pdf (accessed 2026-10-19)