I'm scheduled to do a lactulose breath test for SIBO on Saturday. The only time I've taken lactulose in the past I got very sick. I was vomiting and passed out. I ended up in the emergency room. At the time I was very ill, and that episode happened 10-12 hours after drinking the lactulose, so I'm not sure if that was the actual cause or not. My best guess is that it could have been lactic acidosis from a severe case of SIBO. My SIBO is much better now, so I'm thinking it should be much safer. Plus, this will only be half the amount I took that day. Still, I'm pretty nervous about it. Has anyone else had a bad reaction to lactulose or the breath test?