Bacillus thuringiensis produces delta-endotoxin and it kills insects effectively. It is a type of biological pesticide and it is an important one, since among the global biological pesticide sales, 90% of the market share is accounted by Bacillus thuringiensis products. The delta-endotoxin produced by Bacillus thuringiensis is a target pesticide. The reaction when people inhale heavy amount to Bacillus thuringiensis is just as same as the reaction when people inhale heavy nontoxic particles.