Common causes of vomiting and fatigue include illnesses such as the flu, as well as food-borne illnesses like food poisoning. More serious conditions, such as traumatic brain injuries, can cause vomiting and a feeling of exhaustion; in addition, certain medications can cause nausea and fatigue as well. Overindulgence in alcohol is yet another factor that can lead to these symptoms, and can potentially be deadly if one progresses to alcohol poisoning and does not go to the emergency room.
Vomiting and fatigue symptoms should not last more than 24 to 48 hours; the feelings of fatigue may persist after that, but the vomiting should stop. If it does not, it is best to visit a doctor in order to receive medication to prevent vomiting, because left untreated it can lead to dehydration, which is potentially very dangerous. When vomiting occurs with the flu, or due to food poisoning, for example, it generally does not last more than a day or two.
If one is experiencing vomiting and fatigue due to the flu or food poisoning, it is important to rest and drink clear fluids when possible. Once symptoms begin to improve, plain foods such as broth or crackers can be eaten; it is best to start slowly at first in order to prevent the symptoms from returning. Getting plenty of sleep will help to relieve the feelings of fatigue as well.
Throwing up and fatigue from alcohol will also generally resolve within a few hours. Again, however, vomiting can be a symptom of alcohol poisoning, so it is important to monitor symptoms carefully, and make sure that anyone suffering from these symptoms is improving, and not worsening. Alcohol poisoning requires a trip to the emergency room, otherwise it can cause death. Similarly, if one experiences any type of head trauma and then experiences vomiting and fatigue, it is necessary to visit the emergency room because it can be indicative of a brain injury, and vomiting usually indicates that the brain injury is getting worse.
Medications can sometimes cause vomiting and fatigue as well. Sometimes the symptoms can be alleviated if the medication is taken with food or at a certain time of day, but other times it may be necessary to switch to a different medication. Nausea and fatigue are common symptoms with a number of illnesses, so if it persists despite medication changes or dietary changes, a doctor may need to do some diagnostic testing to determine what is causing the problems.