Exposure-response analyses for efficacy and safety were performed for tigecycline-treated patients suffering from community-acquired pneumonia. Data were collected from two randomized, controlled clinical trials in which patients were administered a 100-mg loading dose followed by 50 mg of tigecycline every 12 h. A categorical endpoint, success or failure, 7 to 23 days after the end of therapy (test of cure) and a continuous endpoint, time to fever resolution, were evaluated for exposure-response analyses for efficacy. Nausea/vomiting, diarrhea, headache, and changes in blood urea nitrogen concentration (BUN) and total bilirubin were evaluated for exposure-response analyses for safety. For efficacy, ratios of the free-drug area under the concentration-time curve at 24 h to the MIC of the pathogen (fAUC(0-24):MIC) of ≥12.8 were associated with a faster time to fever resolution; patients with lower drug exposures had a slower time to fever resolution (P = 0.05). For safety, a multivariable logistic regression model demonstrated that a tigecycline AUC above a threshold of 6.87 mg · hr/liter (P = 0.004) and female sex were predictive of the occurrence of nausea and/or vomiting (P = 0.004). Although statistically significant, the linear relationship between tigecycline exposure and maximum change from baseline in total bilirubin is unlikely to be clinically significant.