My mom bought Manzanilla (oil) for my baby, she told me to use it whenever I feel that baby has colic and put some of it on my baby's hands, feet and back before bath time. I told her that our Pedia dont want us to use any oil since it will make the baby skin iritated. My mom told us that she used it on us but we grew up fine. How will I explain that I dont want to use it on my baby.

I would simply let her know that that was what the doctor suggested. Is your baby's skin more sensitive? I do have friends who tried it on their babies and did not experience any irritation. But if your baby has sensitive skin, just explain that to your mother because everyone is different. What works for one (or even you and your siblings) may not work for your baby. Hopefully she will understand. Good luck!