The regulatory question is muddied by the fact that certain probiotics are unquestionably actual food or drink, not merely dietary supplements, with possible secondary benefits to those taking antibiotics. If I’m already eating yogurt with breakfast every morning, and that yogurt includes half a dozen species of bacteria, some of which (e.g. L. acidophilus) could reasonably be expected to survive past the stomach, and I’m eating it first and foremost because I like it, then at the very least there’s absolutely no reason for me to stop eating this stuff when I’m on antibiotics. Similarly, hefeweizen is arguably a source of Saccharomyces, so you can argue that you’re drinking it for medicinal purposes; if I were on antibiotics and picking a beer off an extensive menu, I might use that as a rationale to choose a hefeweizen over, say, an IPA, but I’d be having a beer in any case. People still jokingly use “medicinal purposes” as an excuse to drink gin and tonic, even in areas where malaria has been effectively exterminated.
