Is it safe to give my 4.5 mo daughter diluted chamomile tea to ease upset tummy/gas pains?

Yes: It has an excellent safety record but use pure chamomile tea and not in a bleached tea bag which contains dioxin. Just a few tablespoons should work. Use only as needed since constant use can interfere with iron absorption. If occasional use works it is safe and helpful. If not, look at other possibilities like lactose intolerance which can be treated with lactinex granules to digest lactose.

A small amount is ok: You can give as much as you would normally give water.

Safe-yes: Recommend-no. I find teas and other potions have little effect on infants, ant the air they swallow while drinking the tea may bloat them more. Simethacone drops is the one agent that seems to provide some relief.