It's not just that. Not all anti-biotics are suitable for all infections - treating a skin infection and a gut infection will tend to require different anti-bio

It's not just that. Not all anti-biotics are suitable for all infections - treating a skin infection and a gut infection will tend to require different anti-biotics. Self medication is possible and, with enough research, can be done successfully and responsibly, but for most people it's really not a good idea.