PURPOSE: To obtain an alopecia-preventing agent and trichogenous agent exhibiting excellent trichogenous effect by using cholera toxin as an active component.

CONSTITUTION: A cholera toxin is used as an active component. It is administered preferably by parenteral administration such as subcutaneous injection and local application and the amount of the active component is 1ng to 1μg. The agent exhibits remarkable dilation action on local vessel, hair- generation promoting action and trichogenous action at the applied part and is effective as an alopecia-preventing agent and trichogenous agent. Cholera toxin is bonded to a receptor on the cell membrane of hair follicle to activate adenylic acid cyclase immediately under the cell membrane and vigorously produce cyclic adenosine monophosphate(cAMP) from adenosine triphosphate(ATP) in a cell. Energy is generated by the decomposition of ATP to form cAMP and the generated energy promotes the function of hair follicle, prevents the fallingoff of hair and promotes the hair generation.