Why vomiting 12+ hours later points elsewhere
Buckwheat reactions, if they occur, strike within 4-6 hours—not after a full night's sleep. Your Yorkie's next-morning vomit suggests another cause: maybe she nibbled grass, ate too fast, or has a mild stomach bug. The buckwheat was likely already digested by then, given its quick processing time in small dogs.
Two tablespoons is a decent portion for a 4 lb dog, but not dangerous—it's roughly 10% of their daily food volume. Some Yorkies have sensitive stomachs that rebel against any new texture, even safe ones. Watch the next meal: if she keeps that down, the buckwheat wasn't the trigger.
How to spot food-related vs. illness vomiting
One isolated vomit with no other signs usually isn't worrisome. Food-related upset often includes heaving up partially digested meals, then acting hungry right after. Yellow bile means an empty stomach, which aligns with your timeline—the buckwheat was long gone by then.
Emergency signs are vomiting more than twice in a day, especially with lethargy or refusing water. Tiny dogs dehydrate fast, so squish the scruff of her neck—if the skin doesn't snap back quickly, she needs fluids. Your Yorkie's single episode doesn't require panic, just observation.
The fiber factor in small breeds
Buckwheat's high fiber content (about 5g per cup) can sometimes bulk up stool or cause gas in toy breeds. Your two tablespoons provided under 1g of fiber—not enough to cause issues unless your Yorkie already has irritable bowel disease. Even then, symptoms would be diarrhea, not vomiting.
Compare this to known Yorkie triggers: fatty meats, dairy, or rawhide. Those commonly cause vomiting within 2 hours. Buckwheat is more like oatmeal—bland and binding. If her next poop is firm and normal-colored, the grain wasn't the problem.
When to suspect the bowl, not the food
Sometimes the vomiting culprit is hidden: a dirty water bowl growing bacteria, a plastic dish scratched by teeth, or leftover grease from last night's chicken. Wash all bowls with hot soapy water and switch to stainless steel if you haven't already.
Yorkies are prone to bilious vomiting syndrome—empty-stomach nausea that strikes at dawn. Try splitting her meals into three smaller portions if this happens again. Buckwheat can actually help settle stomachs when cooked plain, so don't blame the grain unless vomiting happens immediately after eating it.
The full verdict, portion guidance and serving notes are collected on the Buckwheat food facts page.