Medical First Aid Guide


Ingestion of hazardous materials at sea is rare but can occur through attempted suicide, contaminated food or water, or through poor personal hygiene.

Ingestion of a toxic material can cause retching, vomiting (sometimes the vomit is blood-stained), abdominal pain, colic and later diarrhoea. Particularly severe symptoms are caused by corrosives, strong acids, alkalis or disinfectants which burn the lips and mouth and cause intense pain, and rarely perforation of the gut.

Ingested poisons can also produce general toxic effects (e.g. impaired consciousness, convulsions, or heart, liver and acute kidney failure) with or without irritation of the gastrointestinal tract, and such effects can be delayed.

  • Have the casualty rinse mouth with water. Give one glass of water to drink.
  • Observe in a place of safety for at least 8 hours.
  • If a significant amount of material has been ingested and the casualty complains of pain in the mouth or the stomach, give two tablets of paracetamol every 6 hours until the pain is relieved. RADIO FOR MEDICAL ADVICE.

Further advice on ingestion of chemicals: see appendix 10.

  • Vomiting should not be induced!
  • Do not give salt water to induce vomiting, as it may be dangerous to do so.
  • Inducing vomiting by stimulating the back of the throat is usually ineffective and may cause aspiration of the chemical into the lungs, and therefore should not be attempted.
  • Dilution with large amounts of water or other liquid is not recommended as it may increase the absorption of the chemical.
  • Syrup of Ipecac is not recommended, as it may cause aspiration of the chemical into the lungs and there is no evidence of clinical benefit from its use.
  • Activated charcoal is usually not recommended at sea because if unconsciousness occurs it may be inhaled into the lungs. Its use in a given case should always be discussed with the radio medical advice.

Refer to IMGS or equivalent national medical guide.

Signs and symptoms Treatment
Frequent vomiting
  • Frequent and prolonged vomiting is a bad sign. Give 10 mg metoclopramide intramuscularly; repeat 2 hours later if vomiting persists.
  • Do not give solid food.
Bleeding (bright red blood, dark brown “coffee ground” vomit or black, tarry, foul-smelling faeces)
  • If severe bleeding occurs, there may be circulatory collapse: see table 11.
Perforation of the gut (severe pain all over the abdomen, board-like rigidity of the abdominal wall, shock)
  • Arrange for evacuation. The casualty will need to be transferred to a shore hospital as soon as possible.
  • Give 10 mg morphine sulphate and 10 mg metoclopramide intramuscularly, if advised medically.
Note: No bowel sounds are heard on listening to he abdomen with a stethoscope.
Further advice on pain relief: see table 13.
  • If advised medically, give cefuroxime 750 mg intramuscularly every 8 hours and a metronidazole 1 g suppository every 8 hours.
  • Institute a rectal infusion with rehydration salts while awaiting the transfer of the casualty to shore hospital.
  • The intravenous administration of fluids may be required.
Further advice on rectal infusion and other fluid replacement: see appendix 13.
  • If the casualty is free of symptoms 8 hours after ingestion, no further action is usually required.
  • Remember that vomit may be inhaled into the lungs, causing difficulty in breathing; if this occurs, treat as for inhalation: see table 9.
  • A patient who has had significant exposure or any symptoms related to exposure should be kept warm in bed and closely observed for 48 hours and RADIO MEDICAL ADVICE OBTAINED.
  • If ingestion was intentional, continuous observation and medical advice is required. Put casualty ashore as soon as possible for hospital evaluation.

Table 9: Inhalation chemicals

Table 11: Shock