If fasting harms the woman who is breastfeeding by greatly decreasing her milk, or stopping its flow, then it is permissible for her not to fast. She should make up the missed fasts before the next Ramadan. Furthermore, a sum of 900 grams of food like wheat, oat and rice must be paid to the needy believers for each missed day.
It is permissible to use it, but it is najis if the alcohol in it is the type that can causes intoxication. When a person or his clothes comes in contact with a najis alcohol through application of perfume or otherwise, he must purify himself or his clothing before performing prayers and Tawaaf.