Forty patients presenting with first episode genital herpes were randomly allocated to seven day treatment with oral acyclovir alone, placebo alone, oral acyclovir plus co-trimoxazole, or placebo plus co-trimoxazole. Patients receiving acyclovir had significantly shorter periods of viral shedding (p less than 0.001), pain (p = 0.03), and times to lesion healing (p less than 0.05). Averaged over...