Pennicillin

The oldest of the "cillins" and still the best recognized and widely used of the antibiotics

Pros: The precursor for all the rest

Cons: Maybe some stomach issues

Penicillin is a great antibiotic to keep on hand for when unexpected things happen. It's inexpensive and can be purchased over the counter. I typically buy mine at Farm & Fleet along with shot syringes for administering it. There's been many occasions where I have had to use Penicillin and it saved my horse's lives. I highly recommend it, just be sure to read the directions carefully for administering it as to not overdose.

Pros: Inexpensive, can be bought over the counter, works very fast

Cons: you have to be careful not to overdose