They aren't leak PROOF, but they are pretty good at keeping the liquid contained when dropped or knocked over. One warning though, be sure the straw is not in the lid when you put it on the cup. The air that's in the cup will force the liquid out through the straw causing you and the floor to become covered in milk/water/juice.
Re: Take and toss straw cups
my read shelf:
6/20/11 mc @ 5wks
10/19/11 mc @ 17wks- Trisomy 18
IUI #1 4/26/12 BFN
Moving on to IVF in July
37 with DOR...fabulous
ER 7/14/12 6R 5F, ET 7/17 3 embies, beta #1 7/26: 147, beta #2 7/28: 326, beta#3 7/30: 422...ugh, beta#4 7/31: 607...hopeful, beta #5 8/2: 1280, beta #6 8/7: 7184 and u/s shows 1 possibly 2 sacs! 8/14 2 beautiful heartbeats! 9/24 we are TEAM BLUE!!!!!
Yep, learned this lesson myself! lol