Cockroaches are omnivorous insects that are widely eaten. Eat all kinds of food, including bread, rice, cakes, cooked meat and vegetables, fruits and drinks. Especially pasta with fragrance, sweetness and oiliness. Cockroaches are addicted to oil. Among all kinds of vegetable oils, sesame oil is the most attractive. In some places, cockroaches are called "oil thieves".

Among sugar, brown sugar and maltose are the most attractive. Cockroaches often eat other things, such as cotton wool products, leather products, paper, books, soap, wires and so on. In outdoor garbage dumps, sewers and toilets, they eat rotten organic matter and even kill animals.

Cockroach adults also have a longer life span, and German cockroaches have the shortest life span, about 100 days. The longest-lived Periplaneta americana can live for one year. Life span also varies with species and environmental conditions. As for Blattella germanica with the shortest cycle, it usually takes more than two months to complete a generation.

The longest Periplaneta americana takes more than a year. It varies not only with species, but also with temperature, nutrition and other conditions. A fertilized female cockroach can lay more eggs in her lifetime. Periplaneta americana can lay more than 50 eggs at most, so cockroaches are very prolific.