The safety of 5% Amlexanox paste was demonstrated in the following clinical studies: vehicle-controlled safety and efficacy studies; dermal irritation and sensitization studies; single and multiple dose pharmacokinetic studies; and a 28-day in use safety study. Minimal adverse experiences were observed with the 991 subjects that were exposed to 5% Amlexanox paste. No significant irritation or sensitization was associated with 5% Amlexanox paste. Pharmacokinetic studies indicated that systemic levels of Amlexanox are most likely due to normal gastrointestinal absorption with only limited absorption directly through the ulcer. After a 100 mg dose of 5% Amlexanox paste the average maximum concentration of Amlexanox in the serum was 120 ng/ml, occurring 2.4 hours after application. The half-life for elimination of Amlexanox was 3.5 hours, and there was no evidence of accumulation with multiple applications. Overall, the data indicate that 5% Amlexanox paste (Aphthasol) is safe for the treatment of recurrent minor aphthous ulcers.