I had to use the Mylicon gas dropped for my daughter when she was an infant. Well, I used CVS brand, just because they are cheaper and the same thing. I used the gas drops when I thought she had a belly ache (her belly would be really super duper hard), and I would give her the drops and she would fart like crazy, and she wouldn't be as whiney and her belly wasn't hard anymore.
I also never started my daughter on solids (jar food) until she was around 8 months old. I just have her either rice or oatmeal with a little bit of baby fruit mixed in with it. My (well her) doctor didn't recommend it. But, I think every doctor and baby are different.
Even though you didn't ask....I totally recommend Calmoseptine for diaper rash. That stuff works awesome!!! Everything else I have tried (diaper paste, Desitin, A&D) never stacked up to that!!! They use it in hospitals and such, and it works sooooooooo good. I would put it on the rash, and within the next changing (sometimes 2nd changing if its a bad rash) it's gone! Google it :) It's even the same price as all the other stuff.