Vomiting fluid and mucus is an indication that all the food and bile has been passed out after repeated vomiting or that there has been a long period of time without eating before a single episode of vomiting, states Health Hype. Sometimes mucus from the airways may empty out with the vomitus.
Some people naturally have thicker, stickier mucus than others, according to WebMD. Certain conditions, such as an allergy or a bad cold, cause mucus to change character and thicken.
Vomiting is the expulsion of contents located in the upper gastrointestinal tract, says Health Hype. Usually the vomitus contains a combination of food, digestive enzymes, fluids, bile and mucus. After expelling all the food and fluids recently consumed, further vomiting produces only mucus, digestive enzymes, stomach acid and water secreted into the gut. Causes of vomiting fluid and mucus include diet, disease, medication and physiological factors. Toxic substances may also cause vomiting as the body tries to expel toxins from the gut.
The most common complication caused by vomiting is dehydration, notes Healthline. Dehydration can cause dry mouth, fatigue, dark urine and decreased urination. Infants and young children are especially susceptible to these effects, because they have less fluid to sustain themselves. Another complication of vomiting is malnutrition, because the body loses nutrients as a result of failing to digest solid foods. Excessive fatigue and weakness related to frequent vomiting may be an indication of malnutrition.