Bjorn, look for the active ingredient, the antibiotic erythromycin is what you want. I believe it is sold in the US under the trade name Maracyn. If you are not in the US, it is illegal in some countries, the UK for example, to buy antibiotics without a prescription from a doctor, dentist or vet. <<<<<<<<<<<<<<<<<<Spug (Sparrow) London, UK.>>>>>>>>>>>>>>>>>>>>