Research has shown that Lemon Grass can be used as galactagogue (agent which increases breastmilk supply). This is besides the other normal remedies like fenugreek. Some Mothers are not able to consume fenugreek well, thus Lemon Grass may be a healthy alternative.
Lemon grass is one of the main ingredients in postnatal tea which is helping to burn fat too.
Also Read About The Health Benefits of Caffeine-Free Herbal Tea
These are the few links which substantiates benefits of Lemon Grass as galactagogue:
http://www.buzzle.com/articles/benefits-of-lemongrass.html
http://tealover-s.blogspot.com/2011/05/lemongrass-benefits-you-should-know.html
http://www.askanaturopath.com/faqs/breast-milk-supply/p/483