the plastic gel filled teething rings they sell in drugstores. You put them in the fridge for a couple hours. so the baby can chew, teeth on the cold rings. it helps dull the pain naturally. as an alternative, baby orajel works good too.
A lot of times it will help relieve the baby's pain if you put your finger in their mouth (clean finger) and rub/massage their gums. Not joking, this really does help. And also try getting the baby some teething rings so they can chew on them to help them while teething. I hope this helps.
I am a mother of six children and what I found to work the best, was a frozen wet wash clothe from the freezer, for them to chew on. You can wash it, freeze it again and use it over and over. Plus it is really cheap. Good luck. : D