Q. My baby has white patches on his tongue and inside his mouth. What could this be?
A. In all likelihood, it's thrush, an infection caused by a fungus called Candida albicans. This is very common in infants (especially if they've recently taken antibiotics -- the medication can kill off the bacteria that would normally keep candida in check). It can be painful, too.
The usual treatment is a prescription antifungal liquid, such as nystatin or miconazole. You should spread it around the infected areas in your baby's mouth before he can swallow it (squirting it with a syringe into each side of his mouth should do the trick). It usually takes a week or two for the thrush to disappear. Just keep applying the medication, and he should be fungus-free soon.
Until then, scrub and boil his pacifiers and bottle nipples after use to avoid reinfecting him -- and yourself. If you're breastfeeding and your nipples are sore, you could have candida on your skin. In that case, just use some of your baby's medication on your nipples; it should soothe the pain.