If your stools turn black, tarry, and stick to the toilet, go to the emergency department the same day; call 120 if you feel dizzy, break into a cold sweat, or vomit blood

Registration and blood tests cost from a few dozen to around 100–200 yuan. Gastroscopy costs a few hundred yuan. If you are still conscious, go to the emergency department; do not wait for an outpatient appointment. If you are dizzy, sweating cold, or vomiting blood, do not drive yourself.

Six hospitals prospectively registered consecutive patients arriving at the emergency department with upper gastrointestinal bleeding, 2944 in total. Upper gastrointestinal bleeding means bleeding in the esophagus, stomach, or duodenum. Within 6 hours of symptom onset, 36% (1068 people) arrived. Another 20% (576 people) waited more than 48 hours. People with black stools were less likely to reach hospital within 6 hours: odds ratio OR 0.22 (95% CI 0.18–0.28). The study concluded that people with black stools alone, without vomiting blood, delay seeking care. Those arriving later had lower hemoglobin and were more likely to need transfusions. Of those arriving within 6 hours, 27% needed a transfusion (286 people), compared with 42% (791 people) of those arriving after 6 hours. Among the 1068 arriving within 6 hours, 80 died within 30 days, or 7%. Among those arriving after 6 hours, 121 died, or 6%. The two groups were similar. Rates of treatment to stop bleeding were also similar: 18% versus 20%. Eight hospitals in China enrolled 2977 inpatients with non-variceal upper gastrointestinal bleeding. Peptic ulcers accounted for 73.26% of cases. Peptic ulcers are ulcers in the stomach or duodenum. In-hospital mortality was 1.71% (51/2977), compared with 0.73% in people younger than 60 and 8.21% in those aged 80 and older. A systolic blood pressure of at least 70 but below 100 mmHg was associated with higher adjusted odds of death: OR 2.67 (95% CI 1.041–6.866). Systolic pressure is the upper blood pressure reading. The 2018 Hangzhou guideline says that vomiting blood and passing black stools generally establish the diagnosis of acute upper gastrointestinal bleeding. With heavy bleeding and rapid intestinal movement, the stool may also contain fresh blood. Iron supplements, bismuth medicines, and animal blood can also turn stools black. Bismuth medicines are stomach medicines containing bismuth. It takes 24 to 72 hours for hematocrit to reflect the amount of blood lost during this episode. Hematocrit is the proportion of blood made up of red blood cells. The guideline recommends resuscitation-room care for confusion, a pulse above 100 beats per minute, or systolic pressure below 90 mmHg. The same applies to cold, clammy hands and feet, or ongoing vomiting or passing of blood. The UK's NHS says to call emergency services or go to the emergency department if stools contain blood or are black, sticky, and very smelly. The same applies to vomiting bright red blood or material resembling coffee grounds. Do not drive yourself. The NHS page on vomiting blood also says to call emergency services or go to the emergency department if you have vomited blood and feel faint or dizzy, or have cold, clammy, pale skin. The NHS also lists H. pylori infection and regular use of painkillers such as ibuprofen as the two most common causes of stomach ulcers.

Laine L, Laursen SB, Dalton HR, Ngu JH, Schultz M, Stanley AJ (2017). Relationship of time to presentation after onset of upper GI bleeding with patient characteristics and outcomes: a prospective study. Gastrointestinal Endoscopy, 86(6), 1028-1037. https://doi.org/10.1016/j.gie.2017.03.1549；Lu M, Sun G, Zhang XM, et al. (2018). Peptic Ulcer Is the Most Common Cause of Non-Variceal Upper-Gastrointestinal Bleeding (NVUGIB) in China. Medical Science Monitor, 24, 7119-7129. https://doi.org/10.12659/MSM.909560；《中华内科杂志》编辑委员会等 (2019). 急性非静脉曲张性上消化道出血诊治指南（2018年，杭州）. 中华内科杂志, 58(3), 173-180. https://doi.org/10.3760/cma.j.issn.0578-1426.2019.03.005；NHS. Stomach ulcer：「Call 999 or go to A&E if: you're vomiting bright red blood or your vomit looks like ground coffee」「your poo has blood in it, or is black, sticky and very smelly」「Do not drive to A&E」。胃溃疡主要原因：「infection with helicobacter pylori (H pylori) bacteria」「regular use of anti-inflammatory painkillers (NSAIDs), such as ibuprofen」. https://www.nhs.uk/conditions/stomach-ulcer/；NHS. Vomiting blood：「Call 999 or go to A&E if: You or your child are vomiting blood (or have vomited blood) and」「feel faint or dizzy」「have cold, clammy, pale skin」「have black poo」. https://www.nhs.uk/symptoms/vomiting-blood/

The evidence grade is B because the numbers come from observational records and clinical guidelines. No one was assigned to an “immediate care” or “wait at home” group. Thirty-day mortality was similar in people arriving within 6 hours and those arriving later, so the benefit rating is not based on a reduction in deaths. Those arriving later needed more transfusions: 42% versus 27%. Transfusion is a surrogate endpoint, so the benefit is rated “small.” You should still go the same day. At home, you cannot tell whether you might suddenly faint. Older adults and people whose blood pressure is already low are at greater risk; see the in-hospital mortality figures under Benefits. In the first 1 to 3 days after bleeding begins, hematocrit may not yet have fallen. A normal complete blood count does not mean everything is fine. If you are taking iron supplements or stomach medicines containing bismuth, or have just consumed a large amount of animal blood, tell the medical team when you go. These can also turn stools black. If in doubt, go; do not assume the color came from food. After the bleeding has stopped, see Section 1, Item 23 (test for H. pylori) for testing and eradication. For buying omeprazole for acid reflux instead of seeking medical care, see Section 34, Item 6 (go directly to hospital for black stools). You are the main beneficiary. If an older family member passes this kind of stool, their children should take them to hospital that day.