As adults, both beetles are small, 1/16 to 1/8 inch long, oval, and reddish brown in color. The drugstore beetle has 3-segmented, elongated, clubbed antennae, and the cigarette beetle has serrated or saw-like antennae. Mature larvae are 1/16 to 1/8 inch long, white, C-shaped grubs with many short hairs.

Both species lay tiny white eggs in and near items to be used as food. Eggs hatch within a few days and grow through 4 to 6 larval stages. Pupae spin a silken cocoon that is covered with debris. The life cycle takes 3 to 7 months and there are overlapping generations. Adults are attracted to light and can fly.

Both beetles will invade a huge number of foods, including spices, dry dog food, drugs, items made of leather or hair, flour, meal, dried fruits and vegetables, yeast, rice, dried beans, and sometimes book bindings.