Active ingredient: JBL Gyrodol: Praziquantel. JBL Oodinol: Copper
How to use (from the label): JBL Gyrodol: Usually a single treatment (10 ml per 40 l for Gyrodol 2); repeat after one week for egg-laying gill flukes.. JBL Oodinol: About a 10-day course: day 1 10 ml/100 l, then test copper and redose on days 2, 3 and 5 to hold 0.3 mg/l; raise temperature by 3 °C (max 30 °C); at least 70% water change at the end.
Careful: Oodinol (copper): too much copper kills fish; toxic to many invertebrates and algae, so treat in a quarantine tank; many catfish are sensitive; test copper daily; it harms filter bacteria; remove carbon, UV and CO2. Gyrodol: no warning found.
Rules: Praziquantel (Gyrodol) was taken off Germany's list of freely sold (OTC) medicines for a time and was put back on it by 2011.
Never mix medicines unless the label says it is safe, and remove shrimp and snails unless the label says they are safe.
Examples you may see in shops: JBL Gyrodol Plus 250 (Gyrodol 2), JBL Oodinol Plus 250. Not endorsements. Always follow the label.
6 facts checked with sources