Ladybugs, also known as ladybirds or lady beetles, are generally harmless to humans and pets. While they do produce toxic chemicals, the primary effect of the chemicals is to make the beetles smell and taste bad to predators. Ladybugs can bite, but the bite is harmless and only slightly painful.
Ladybugs are widely known as beneficial insects because they have an insatiable appetite for many crop pests, particularly aphids. Some species, particularly the introduced multicolored Asian lady beetle, can be mild nuisances when they move into homes or other buildings for the winter. Another species, the Mexican bean beetle, feeds on bean leaves and pods and is an agricultural pest.