Yes, but don't overdo it. When caffeine enters your bloodstream, a small amount of it (usually less than 1 percent) ends up in your breast milk. Your baby's body can't easily break down and excrete caffeine, especially in the first few months of life, so over time it may accumulate in his system.
Drinking a lot of coffee (more than two or three cups day), for example, might cause one or both of you to become irritable, jittery, or agitated, and it can contribute to sleeping problems. But many experts say that moderate intake of caffeine (usually defined as no more than 300 mg per day) is fine for nursing moms, causing no changes in most babies' behavior.
That said, every baby is different. If your baby seems to be bothered when you have caffeine — even in limited amounts — you may want to cut it out of your diet for a while to see if that makes a difference.
What are the main sources of caffeine?
Coffee is one, of course. The amount of caffeine in a cup of coffee varies widely, depending on the type of bean, the brewing method, and how strong it's brewed. And your serving size depends on the size of the coffee cup.
To cut your caffeine intake, though, you'll need to be aware of other sources, like tea, soft drinks, "energy" drinks, chocolate, and coffee ice cream. Caffeine also shows up in herbal products and over-the-counter drugs, including some headache, cold, and allergy remedies.
Caffeine chart: Amounts in common foods and beverages
Coffee Amount Caffeine
coffee, generic brewed 8 oz 102-200 mg
coffee, Starbucks brewed 16 oz (grande) 330 mg
coffee, Dunkin' Donuts brewed 16 oz 206 mg
caffé latte or cappuccino, Starbucks 16 oz (grande) 150 mg
caffé latte or cappuccino, Starbucks 12 oz (tall) 75 mg
espresso, Starbucks 1 oz (1 shot ) 75 mg
espresso, generic 1 oz (1 shot) 30-90 mg
coffee, generic instant 8 oz 27-173 mg
coffee, generic decaffeinated 8 oz 3-26 mg
Tea Amount Caffeine
black tea, brewed 8 oz 40-120 mg
green tea, brewed 8 oz 30-50 mg
decaffeinated black tea 8 oz 2 mg
Starbucks Tazo Chai Tea latte 16 oz (grande) 100 mg
Nestea 12 oz 26 mg
Snapple 16 oz 42 mg
Lipton Brisk iced tea 12 oz 10 mg
Soft drinks Amount Caffeine
Coke 12 oz 35 mg
Pepsi 12 oz 38 mg
Jolt Cola 12 oz 72 mg
Mountain Dew 12 oz 54 mg
7-Up 12 oz 0 mg
Sierra Mist 12 oz 0 mg
Sprite 12 oz 0 mg
Energy drinks Amount Caffeine
Red Bull 8.3 oz 80 mg
SoBe Essential Energy, berry or orange 8 oz 48 mg
SoBe No Fear 8 oz 83 mg
Desserts Amount Caffeine
dark chocolate 1.45-oz bar 31 mg
milk chocolate 1.45-oz bar 11 mgjavascript:void(0)
coffee ice cream or frozen yogurt 8 oz 50-60 mg
hot cocoa 8 oz 3-13 mg
http://www.babycenter.com/0_caffeine-and-the-nursing-mom_4488.bc
