The purpose of this clinical investigation is to confirm the efficacy of eliminating facial wrinkles by injecting botulinum toxin A into mimetic muscles. Fifty-four patients were injected with BOTOX A-14 in the corrugator superciliaris, 19 in the frontalis muscles, and 13 in the orbicularis oculis. Dilution was obtained by adding 4 ml preservative-free saline to 100 IU of BOTOX A. The dose used varied according to the patient. The severity of wrinkles and the intensity of muscle contraction (facial expression) were taken into account. The paralysis obtained in the mimetic muscles was effective for 6 months in 39 patients, 8 months in 10 patients, and 9 months in 1 patient. The results were documented by photographs, videotape, and electromyographies pre- and postinjection. To preserve the results, 21 patients (39%) demanded a second infiltration to achieve satisfactory results. Neither local nor general adverse effects were noted, except transitory eyebrow palsy in 2 patients, and edema and ecchymosis in 4 patients. The improvement obtained in facial mimetic wrinkles was satisfactory to the patient and to us.