Patients who have exaggerated frown lines frequently ask for treatment because others mistake them to be constantly angry or annoyed. Current treatment options (surgery or implants) do not address the underlying cause of these lines, namely the excessive nerve stimulation. The mechanism of action of BTX makes it an ideal agent to target the major cause of these lines. BTX inhibits calcium metabolism in the presynaptic neuron, thereby inhibiting neuromuscular transmission and producing muscle paralysis. The current medical literature indicates that BTX can be used safely and effectively for the cosmetic treatment of frown lines. The procedure can be performed in an ambulatory setting and the use of an EMG instrument may provide better direction for the placement of the drug. However, the benefits are transient and repeated injections are necessary. The adverse effects associated with BTX injections were mild and transient. Currently, there are no safety data on the long-term effects of continuous BTX injections for the treatment of frown lines. However, studies on the long-term use of BTX at doses to treat blepharospasm and Meige's disease have shown no serious adverse effects or production of antibodies to BTX. Muscle biopsies taken from patients who have received numerous doses of BTX for more than 7 years have not shown any signs of atrophy or permanent muscle degeneration. The medical literature supports BTX therapy as an option for the treatment of cosmetic facial frown lines. However, there is not enough information on what patient characteristics are ideal in a candidate to achieve optimal response with BTX. Also, no data are available on the safety and efficacy of continuous injections in the long-term use of BTX for facial frown lines. Therefore, the use of BTX to treat frown lines should be examined carefully against other therapeutic options.