Can breast milk and formula be mixed?

That's like driving F1 car on roads, or a polo on a circuit. Its not scary, but it isn't recommended. try not to dilute the natural healthy milk with something that's like water up against. But if it's because of low breastmilk supply, I'd suggest take doc's suggestion on how you can improve. Or you can read online some causes http://www.todaysparent.com/baby/baby-health/10-reasons-for-low-milk-supply-when-breastfeeding/