My daughter has severe acid reflux. Around 10 days she was crying inconsolably until her face was purple, wouldn't sleep, was spitting up a ton and then screaming some more. We took her to the dr. where she was diagnosed. She was at that time put on .8 ml Zantac 2 times a day and it has increased appropriately w/ her weight gain. We also keep her upright for about 20 mins after eating, her crib mattress is inclined also. She still spits up A TON but it doesn't burn her throat like before the Zantac. Also, at about 2 1/2 months, per our pedi, rice cereal was added to her bottles to keep her formula/BM down due to the amount she was spitting up.
We have also used gripe water when she was particularly fussy. Basically, it's a mix of herbs like ginger that naturally settle the belly. It can be used for gas, colic but not for reflux.
As fas as gas drops go we used the Littles Ones gas drops and they worked great. The only thing you have to remember is that gas drops are only for air that gets into the belly not intestinal gas. For intestinal gas try doing bicycles w/ baby's legs, rubbing the belly, massaging.