Green vomit can be unsettling, but it may not always indicate a serious problem. The presence of this color usually relates to substances found lower down in the digestive system. While it may simply reflect a stomach emptied by repeated retching, the appearance of green liquid can also signal a significant medical condition.
Why Vomit Turns Green
The green color in vomit is directly linked to the presence of bile, a fluid produced by the liver. Bile is stored in the gallbladder before being released into the small intestine, where it helps emulsify fats during digestion. The specific green hue comes from biliverdin, a pigment resulting from the breakdown of red blood cells, which gives bile its characteristic dark green or yellowish-green color.
For bile to appear in vomit, it must travel backward, or reflux, from the small intestine into the stomach. The pyloric sphincter, a muscular valve between the stomach and the small intestine, usually prevents this backflow. Vomiting bile suggests the sphincter was relaxed or overcome by pressure, allowing the fluid to be expelled.
Transient and Common Causes
In many instances, green vomit is a consequence of prolonged or forceful vomiting, not a severe underlying illness. When the stomach is completely emptied of food and digestive acid, continued retching can cause bile to reflux from the small intestine. This often occurs with conditions like viral gastroenteritis (stomach flu) or severe morning sickness (hyperemesis gravidarum), especially when the stomach is empty.
A simpler explanation is the recent consumption of green-colored food, drinks, or candy, which can temporarily tint the vomit. However, this is distinct from bile-related green color.
Acute and Serious Medical Reasons
While many causes of green vomit are temporary, the color can signal an acute, serious problem involving a blockage in the digestive tract. An intestinal obstruction occurs when food or fluid cannot pass through the intestine, creating a backup. This mechanical obstruction leads to pressure buildup that forces bile and other contents back into the stomach.
Causes of Obstruction
In adults, the most common cause of small bowel obstruction is the formation of adhesions, bands of scar tissue that develop after previous abdominal or pelvic surgery. Other mechanical obstructions include hernias, tumors, or strictures caused by inflammatory conditions like Crohn’s disease. A non-mechanical form is paralytic ileus, where muscle or nerve issues temporarily halt intestinal contractions, mimicking a physical blockage.
A blockage in the small intestine is considered a medical emergency because pressure buildup can compromise blood flow to the affected section of the bowel. This can lead to tissue death, perforation, and the release of harmful bacteria. In infants and young children, intussusception, where one segment of the intestine telescopes into another, is a serious cause of obstruction often presenting with bile-stained vomiting.
Warning Signs and When to Contact a Doctor
The appearance of green vomit alone is not always alarming, but when combined with certain symptoms, it warrants immediate medical evaluation.
Seek immediate medical attention if you experience:
- Inability to pass gas or stool, indicating a complete intestinal obstruction.
- Severe, persistent, or worsening abdominal pain or cramping.
- Signs of dehydration, such as excessive thirst, a dry mouth, or infrequent urination.
- A high fever accompanying the green vomit.
- Vomiting that lasts longer than 48 hours, or the inability to keep down any fluids.
- Confusion, lightheadedness, or sudden weakness, which suggest a serious condition.