Gastroenteritis, commonly called a stomach bug, is an inflammation of the stomach and intestines that causes rapid fluid loss through vomiting and diarrhea. This loss of fluid and electrolytes, such as sodium and potassium, makes dehydration the most significant complication of the illness. Maintaining the body’s fluid and electrolyte balance is the primary goal of home care. Effective rehydration requires understanding fluid absorption, using specific drinking techniques, and knowing which substances to avoid.
The Hydration Standard: Oral Rehydration Solutions
Drinking plain water or highly sweetened liquids is often not enough to correct the imbalance caused by a stomach bug. Vomiting and diarrhea deplete water and essential salts required for the body’s functions. Standard water cannot replace these lost electrolytes, and sugary drinks can draw water into the intestines, potentially worsening diarrhea.
The gold standard for rehydration is an Oral Rehydration Solution (ORS), precisely formulated to maximize fluid uptake across the intestinal wall. The efficacy of ORS relies on the sodium-glucose cotransport system. This biological mechanism requires the presence of both sodium and a small amount of glucose to pull water into the bloodstream.
When consumed, the glucose molecule acts as a vehicle, binding with sodium at the intestinal cell wall to facilitate joint absorption. This co-transport passively pulls water in through osmosis, rapidly restoring fluid and electrolyte levels. Commercially prepared ORS powders or pre-mixed solutions are recommended because they contain the exact balance of sugar and salts needed for this specialized absorption.
Strategies for Successful Fluid Retention
When experiencing nausea and vomiting, the method of consuming fluids is key. It is helpful to first allow the stomach to rest completely for 20 to 30 minutes after the last episode of vomiting. This brief pause reduces stomach irritation and improves the chances of retaining the next fluid intake.
Once the stomach has settled, begin rehydration by taking very small, frequent amounts of ORS. Aim for controlled sips, such as one or two teaspoons every few minutes, rather than drinking from a glass or bottle. This slow, steady intake allows the stomach to absorb the fluid without becoming distended, which can trigger further vomiting.
Sucking on ice chips or popsicles made from an Oral Rehydration Solution is also an effective strategy, especially for those with severe nausea. The frozen form forces a slower rate of intake, and the cold temperature may soothe an irritated stomach lining. Only gradually increase the volume of fluid if small amounts are tolerated without renewed vomiting.
Liquids and Foods to Avoid
Certain common beverages and foods can actively interfere with recovery and should be avoided during acute gastroenteritis. High-sugar drinks, including fruit juices, sodas, and undiluted sports drinks, contain too much sugar relative to their salt content. This high concentration of sugar creates an osmotic effect in the intestines, pulling water out of the body and into the bowel, which intensifies diarrhea.
Drinks containing caffeine, such as coffee, tea, and some soft drinks, should also be avoided. Caffeine is a diuretic that encourages fluid loss through urination and can irritate the digestive tract, potentially increasing the frequency of bowel movements.
Following a stomach bug, many people develop a temporary inability to digest lactose because the illness can damage the necessary enzymes. For this reason, dairy products, including milk and ice cream, should be avoided for a few days, even after other symptoms have improved. Temporary lactose intolerance can otherwise prolong diarrhea and abdominal discomfort.
Recognizing Warning Signs of Dehydration
While home management is effective for most stomach bugs, it is important to recognize the signs that dehydration has progressed and requires professional medical care. In adults, warning signs include an inability to keep any fluids down for 12 to 24 hours, or experiencing dizziness when standing up. Other indicators are extreme thirst, a dry mouth, or not urinating for eight hours or more.
For infants and young children, signs of severe dehydration can develop more quickly and require immediate attention:
- A lack of wet diapers for six to eight hours.
- The absence of tears when they cry.
- Visibly sunken eyes or a sunken soft spot (fontanelle) on an infant’s head.
- Excessive lethargy or irritability.
Other red flags for all ages signal the need for medical evaluation. These include a persistent high fever, severe abdominal pain, or the presence of blood or pus in the stool or vomit. If these severe symptoms occur, or if milder dehydration symptoms do not improve despite using Oral Rehydration Solutions, seek prompt medical attention.