Most women that did have negative feedback for these vitamins commented about them not seeing an increase in their production of breastmilk. This may be because they did not use the recommended dosage, or they did not take them consistently. These may not give good results right away, so it is important to take them regularly as directed until you see a difference, or they do not agree with you. Another popular comment was that either the mother or the infant became gassy when using a multivitamin. This may be just an individual occurrence because these should not induce gas. Make sure to drink plenty of water to increase hydration at this important time of breastfeeding and to also get plenty of exercise. This should cut down on the gassy build-up of the mother. With proper burping, infants should not be gassy either.