Twenty-one samples of traditionally-prepared (home-made) and ready-made (commercial) St. John's Wort olive oil macerates were profiled for their in vitro antimicrobial and antiprotozoal activity. Their cytotoxic potential was evaluated on MRC-5 fibroblasts. In the antiprotozoal assays, ten of the oils inhibited Trypanosoma brucei rhodesiense (IC50 15.9-64.5 mu g/mL), while only one oil exerted antimicrobial activity towards Staphylococcus aureus (IC50 = 88.7 mu g/mL). LC-DAD-MS data revealed the presence of pseudohypericin (0.135-3.280 mu g/g) and hypericin (0.277-6.634 mu g/g) in all the oils, whereas chlorogenic acid (1.063 mu g/g) was detected only in one oil sample. Hyperforin was detected in four (0.977-2.399 mu g/g) and adhyperforin in six samples (0.005-3.165 mu g/g). Hypericin and pseudohypericin were common in the active oils, whereas hyperforin, adhyperforin, and chlorogenic acid were absent in these samples. Our results indicated that if the correct plant material is used, the infused oils from Hypericum perforatum may contain active components. (C) 2012 Elsevier Ltd. All rights reserved.