It's been crazy hot out during the past 3-4 days and I've been bringing Holly swimming in our river a couple of times per day to keep her cool, or else she is just miserable. She is a 2 yr old lab so she definitely has the energy to be swimming. I've been throwing her ball for her in the deep water so she can swim rather than walk on the rocks. She absolutely loves it and will sometimes even dive under water to get her ball before it floats back up. She opens her mouth so she is probably swallowing a lot of water. She has been acting completely normal and eating and drinking like she always does. Still the same extremely happy dog. But, 3 nights ago, around midnight she started coughing like she was going to vomit. She sleeps in my bed so I was able to hear her. So I got up fast and brought her outside. She vomited grass and bile. She has been eating a LOT of grass, around the river, even though we try to stop her. The grass did not look chewed in her vomit. I didn't worry too much about it, since dogs sometimes get into bad stuff and she seemed fine. The next night she was fine and didn't vomit. But last night she did it again around 4 am. She jumped out of bed on her own and looked stared at me until I let her out. Could it be the humidity and heat making her nauseous? I have a fan on her all night, but it has been pretty hot during the past nights. Or might it be all the water she swallowed at once irritating her stomach? We just got her 3 months ago and just had her spayed and she has been to the vet's about 5-6 times since we have had her, so I don't want to be making any useless trips there. But if she continues to do it I definitely will. Tonight is a lot cooler so I will se how she does. Thanks in advance.