Understanding the History of Medical Nutrition: Why is it called St. Mark's solution?

October 6, 2025 •

3 min read

Developed by London's renowned St. Mark's Hospital, this specialized oral rehydration solution has been used for decades to treat patients with severe dehydration due to high intestinal output. The answer to Why is it called St. Mark's solution? lies within its institutional origins and its crucial role in medical nutrition.

Quick Summary

This article explains how the specialized oral rehydration mix was developed at a London hospital to manage severe dehydration in patients with conditions like short bowel syndrome.

Key Points

Hospital of Origin: St. Mark's solution is named after St. Mark's Hospital in London, where it was originally developed for its specialized patients.
Specialized Formulation: Unlike standard oral rehydration solutions, it is potassium-free to prevent hyperkalaemia in patients with intestinal failure.
High Sodium Content: The solution contains a higher sodium concentration to maximize fluid and electrolyte absorption in compromised intestines.
Management of Intestinal Failure: It is primarily used to treat patients with short bowel syndrome, high output stoma, or intestinal fistulas.
Home Preparation: The solution is not commercially available and must be made fresh daily by the patient using simple, inexpensive ingredients like glucose, salt, and baking soda.
Part of Medical Nutrition Therapy: Its use is a critical component of medical nutrition therapy, helping to manage fluid balance and reduce the need for intravenous fluids.
Avoidance of Hypotonic Fluids: Patients are advised to limit other fluids like water, tea, and coffee, as these can increase fluid loss in individuals with intestinal failure.

The Origin Story: Why is it called St. Mark's solution?

St. Mark's solution is an oral rehydration solution (ORS) named after its origin at St. Mark's Hospital in London, a pioneering center for colorectal and intestinal medicine with a long history of specializing in intestinal diseases. The hospital’s clinicians and dietitians created the solution to address the specific needs of patients with intestinal failure, particularly those with a high output stoma or short bowel syndrome. Existing oral rehydration products were unsuitable due to their electrolyte profile, which posed risks to these patients. The hospital developed a custom, non-commercial recipe using inexpensive ingredients, designed specifically for their patients.

The Clinical Problem St. Mark's Addressed

Patients with intestinal failure, such as from short bowel syndrome, face significant challenges in maintaining fluid and electrolyte balance due to reduced ability to absorb water and nutrients. This often results in high fluid loss and chronic dehydration. Standard ORS were not ideal because some contain potassium, which can be dangerous for these patients, and hypotonic fluids like water can worsen fluid loss. St. Mark's solution is designed to be potassium-free and has a high sodium content to counteract these issues and promote absorption.

The Nutritional Science of St. Mark's Solution

The solution is a glucose-electrolyte mix formulated to be isotonic, mimicking blood plasma to maximize salt and water absorption. Its high sodium concentration is crucial for stimulating absorption, while glucose acts as a co-transporter, aiding in sodium and water uptake, which is vital for patients with compromised intestinal function.

How to Prepare St. Mark's Solution

St. Mark's solution is not commercially available and must be prepared daily. It is a specific mix of glucose, sodium bicarbonate, and sodium chloride in cold tap water.

Key components:

Glucose powder.
Sodium bicarbonate powder (baking soda).
Sodium chloride (table salt).
Cold tap water.

Preparation overview:

Measure dry ingredients accurately.
Add ingredients to water and stir until dissolved.
For taste, it can be chilled or a small amount of lemon/lime squash can be added.
Any unused solution should be discarded after 24 hours.

St. Mark's Solution vs. Other Oral Rehydration Options

St. Mark's solution's unique composition distinguishes it from other rehydration products:


Feature	St. Mark's Solution	Standard WHO-type ORS	Sports Drinks
Primary Use	Intestinal failure, high output stoma, short bowel syndrome	Cholera, diarrhea, general dehydration	Exercise-related rehydration, energy replenishment
Potassium Content	Potassium-free	Contains potassium	Contains potassium
Sodium Concentration	High sodium	Standard sodium (~75mmol/L)	Lower sodium
Sugar Content	Optimized glucose for co-absorption	Specific glucose amount for rehydration	Often very high sugar
Availability	Non-commercial, home-prepared	Widely available commercially	Widely available commercially

Integrating St. Mark's into Medical Nutrition Therapy

St. Mark's solution is a key element in personalized medical nutrition therapy for patients with intestinal failure, helping to manage fluid balance and potentially reduce the need for intravenous fluids. Patients are advised to sip it slowly and limit hypotonic fluids.

Conclusion: A Legacy of Specialized Nutrition

St. Mark's solution is a significant contribution to medical nutrition, named after the hospital where it was developed to meet a specific clinical need for which no suitable commercial product existed. Understanding why is it called St. Mark's solution? highlights the importance of tailored nutritional interventions for conditions like intestinal failure. This simple, home-prepared mix remains vital for preventing dehydration and electrolyte imbalances, improving the quality of life for many patients. For clinical details, the Specialist Pharmacy Service is a valuable resource.

Frequently Asked Questions

St. Mark's solution is used for the management of intestinal failure, high output stomas, and short bowel syndrome, which are conditions that can lead to severe dehydration and electrolyte imbalance.

The main difference is its potassium-free and high-sodium composition. This formulation is specifically designed to address the risks of hyperkalaemia and poor sodium absorption common in patients with certain intestinal disorders.

St. Mark's solution is prepared by combining specific amounts of glucose powder, table salt (sodium chloride), and sodium bicarbonate (baking soda) with cold tap water.

Yes. Storing it chilled in the refrigerator, freezing it into a slush, sipping it with a straw, or adding a small amount of lemon or lime squash to the full batch can improve the taste.

For patients with intestinal failure, drinking plain water (a hypotonic fluid) can increase fluid loss from the body, worsening dehydration and electrolyte issues. St. Mark's solution is designed to promote fluid and sodium absorption.

The solution can be stored at room temperature or in the fridge, but it must be discarded after 24 hours. A fresh batch should be prepared daily.

Sports drinks are not suitable for this purpose. They often have high sugar and low sodium concentrations, which is not beneficial for clinical rehydration and can worsen fluid loss in these patient populations.