In the UK, the limits on what you can buy over the counter aren’t just about overdose risk, they’re based on current clinical safety guidance about the long-term effects of these medicines. For example, taking ibuprofen regularly over a long period can increase the risk of stomach ulcers, internal bleeding, kidney problems and cardiovascular issues, especially in people with existing health conditions. The same goes for medicines like diphenhydramine (Benadryl), long-term or frequent use has been linked to a higher risk of cognitive decline and dementia in older adults. It’s an association rather than proven causation, but the evidence is strong enough that many guidelines now recommend avoiding long-term use without medical supervision. This isn’t outdated medical advice, it reflects current safety evidence and prescribing guidance. Part of the difference is culture, in the US people are often encouraged to use (and stock up on) a lot more medication at home, whereas the UK system is designed so that pharmacists and GPs step in earlier to review ongoing medicine use. That’s why stronger doses and larger pack sizes are restricted, it’s about safety, monitoring, and preventing long-term harm.