We don't have a UK guideline for a safe amount of caffeine for breastfeeding mums. In the US, women who are breastfeeding are recommended to have no more than about 200mg of caffeine a day (ACOG 2013, COD 2001) . That's about two mugs of tea, or two mugs of instant coffee, or one mug of filter coffee, a day (FSA 2008) . More than this amount of caffeine is unlikely to harm your baby (COD 2001, Briggs et al 2011) .