Ants are common household pests. They don’t carry disease, but can be annoying.

Argentine ants are the most common cause of ant invasions indoors, but other species may cause problems in this area. Knowing which ant is causing your issue is important, since different ant species have different food preferences and will take different types of bait. For ant identification and control information, contact the District laboratory at (650) 344-8592.

If you see ants indoors, your first impulse will probably be to kill the ants that are inside, but don’t reach for the bug spray! Insecticide sprays aren’t usually needed for ant infestations. Instead, you can wipe up the ants with a damp soapy sponge, or even vacuum them up.

Next, you’ll want to stop additional ants from coming in. Clean up or remove whatever the ants are feeding on, then wipe away ant trails with soapy water. Entry points can be sealed with caulk to keep ants out.

In many cases, this is enough to stop the problem. If ants continue to invade, you may need to use an ant bait to kill the colony. Place bait stations near where you see ants entering.

For more information on ants, visit the UC IPM webpage.

Page last reviewed: June 10, 2021