Antibiotic for toddler?

If he has an actual diagnosed bacterial infection he should take the antibiotic as prescribed. If it's a viral infection an antibiotic will not work. There are many flavoring methods available to make the test better, ask your pharmacist what you can do to make the test better since if he's unwilling to take it (spits it out/vomits) it's not getting ingested and not doing any good.