Bacillus thuringiensis (Bt)

Bacillus thuringiensis (Bt) is a species of bacteria that lives in soil. It makes proteins that are toxic to some insects when eaten, but not others. The proteins are not toxic to humans because, like all mammals, we cannot activate them. Bt is not toxic to non-target wildlife. However, one type of Bt (aizawi) can be toxic to honeybees. Bt is used as an insecticide, typically, for insect larvae. Remember, it has to be eaten to work.

Information about Bt

• What is Bt?
• What are some products that contain Bt?
• How does Bt work?
• How might I be exposed to Bt?
• What are some signs and symptoms from a brief exposure to Bt?
• What happens to Bt when it enters the body?
• Is Bt likely to contribute to the development of cancer?
• Has anyone studied non-cancer effects from long-term exposure to Bt?
• Are children more sensitive to Bt than adults?
• What happens to Bt in the environment?
• Can Bt affect birds, fish, and other wildlife?

Bt Fact Sheet (Web | PDF)

Bt Strains Infographic

Bt Video (6:14 min.)

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If you have questions about this, or any pesticide-related topic, please call NPIC at 800-858-7378 (8:00am - 12:00pm PST), or email at npic@ace.orst.edu.