Short answer

A small one-time amount of mucus with no other symptoms may be observed. Arrange an appointment when it is new and keeps returning. Seek urgent care for bloody diarrhea, black or dark red stool, significant bleeding, severe pain, high fever, repeated vomiting, faintness, or dehydration.

Get urgent medical help

  • Black, tar-like, or dark red stool
  • Bloody diarrhea or substantial rectal bleeding
  • Severe or rapidly worsening abdominal or rectal pain
  • Fainting, confusion, marked weakness, or shortness of breath
  • Repeated vomiting or inability to keep fluids down
  • Signs of significant dehydration, including very little urine and dizziness

Arrange a timely appointment

  • Mucus is noticeably increasing, persistent, or repeatedly returns
  • There is an ongoing change in bowel habits
  • Diarrhea lasts more than two days without improvement in an adult
  • You have pain, urgency, fever, fatigue, or unexplained weight loss
  • Symptoms began during or after antibiotics
  • You are concerned, even if the pattern does not fit a list

When brief observation may be reasonable

A very small amount seen once, with otherwise normal bowel movements and no pain, fever, blood, weight loss, or illness, may not require emergency care. Record it and watch for recurrence rather than repeatedly inspecting every bowel movement.

People who may need earlier advice

Infants and young children, older adults, pregnant people, and people who are immunocompromised or have significant bowel disease can become unwell or dehydrated more quickly. Contact an appropriate clinician sooner for new or concerning symptoms.

Sources

We prioritize public-health agencies and established clinical institutions. Accessed August 19, 2026.