How to Prepare Dakin's Solution (0.5% Sodium Hypochlorite)
To prepare sterile Dakin's solution for wound irrigation, mix 100 mL of household bleach (5-6% sodium hypochlorite) with 8 teaspoons of baking soda into one gallon of clean water, or alternatively, mix 25 mL bleach with 2 teaspoons baking soda into one liter of water. 1
Standard Preparation Method
The most practical and widely validated formulation for wound care uses the following ratios:
- Large volume preparation: 100 mL household bleach + 8 teaspoons baking soda + 1 gallon clean water 1
- Small volume preparation: 25 mL household bleach + 2 teaspoons baking soda + 1 liter clean water 1
This produces an approximately 0.5% sodium hypochlorite solution suitable for wound irrigation and post-surgical wound care 1.
Alternative Concentrations for Specific Uses
For burn wound infections and highly contaminated wounds, lower concentrations may be more appropriate to balance antimicrobial efficacy with tissue toxicity:
- 0.006% solution is the minimum bactericidal concentration for common pathogens including Pseudomonas aeruginosa, Staphylococcus aureus, and Streptococcus pyogenes, while maintaining 24% fibroblast viability 2
- 0.025% solution (modified Dakin's) has demonstrated clinical efficacy against severe infections including Vibrio vulnificus 3
- 0.1% solution has shown superior outcomes in diabetic foot ulcer management compared to normal saline irrigation 4
Field-Expedient Preparation
When sterile irrigation fluid is unavailable, ground-derived field water can be treated with 5% sodium hypochlorite to achieve a final concentration of 0.025%, effectively eliminating bacterial contamination in 99% of samples. 5 This method has been validated for military forward surgical teams when logistical constraints prevent access to commercial sterile irrigants 5.
Storage and Stability Considerations
Un-buffered sodium hypochlorite solutions maintain bactericidal efficacy for at least 6 consecutive days when stored at room temperature, with pH and electrolyte concentrations remaining stable for 14 days. 2
- Store in closed, dark, cool, and dry containers 6
- Use as soon as possible after opening 6
- Do not dilute with hot water above 40°C 6
- Normal to observe floating objects and sediments 6
Safety Precautions During Preparation
Wear gloves during preparation and avoid skin contact with the original concentrated solution; if contact occurs, rinse immediately with water. 6
- If solution contacts eyes, immediately rinse with copious water 6
- The solution is corrosive to metals and will bleach fabrics 6
- Do not mix with other disinfection products 6
Clinical Application Guidelines
Once prepared, wet gauze with the solution, place on the wound, and replace every 24 hours as needed. 1 This method has proven effective and safe for post-surgical wound care in both resource-limited and well-resourced environments 1.
For environmental surface disinfection in healthcare settings, use a 1:100 dilution (500-615 ppm available chlorine) for routine decontamination of nonporous surfaces after cleaning blood or body fluid spills. 7 For large spills involving significant blood or culture material in laboratories, use a 1:10 dilution (5,000-6,150 ppm available chlorine) for initial application before cleaning 7.
Important Caveats
The alkaline hypochlorite solution is recommended for intact skin and soft tissues only and is contraindicated for eye, brain, and abdominal wounds. 8 For intermediate-level disinfection of noncritical instruments with visible blood, use a 1:50 dilution (1000 ppm chlorine) 9, while environmental surfaces without visible blood require only a 1:500 dilution (100 ppm chlorine) 9.
Contact poison control centers promptly after any bleach ingestion, as routine administration of milk or water is not advised and activated charcoal should not be used. 10