One hundred and ninety-six hospitalized patients were randomly assigned to one of eight treatment groups consisting of oral or intramuscular analgesics and placebo. Patients were monitored for 6 hours for pain relief, vital signs, and side effects. No statistically significant differences in pain intensity or relief were seen for nefopam (Acupan), diphenhydramine (Benadryl), aspirin, or placebo despite a numerically higher score for nefopam. This is attributed to an unexpectantly high placebo response. Significant pain relief and reduction of pain intensity were seen with both parenteral nefopam and morphine. Side effect incidence, in general, paralleled analgesic efficacy and was higher in patients receiving parenteral drugs. An early hypothermic effect was noted with oral and parenteral nefopam, aspirin, and morphine. Lower temperatures persisted to a statistically significant degree only in nefopam-treated patients.