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Drink Driving and Herbal Tinctures

Make sure you know your alcohol limit and don't break the drink driving laws.

by Monica Wilde
5 December 2014


Here in Scotland, the law changed today restricting the amount of alcohol you can drink before you drive. You need to be aware that if you are using a herbal tincture as a food supplement or as a medicine that this will have an additive effect. It will lower the amount of units of alcoholic drinks that you can have.

Know you alcohol limitsIn Scotland the limit for safe, driving is now 50mg per litre of blood, not 80 mg per litre as it is in England and Wales. Each person is different as their weight and metabolism varies. Other factors like whether you have eaten anything also affect your alcohol intake. Here is a handy table to calculate how many units of alcohol a herbal tincture can add to your alcohol intake.

On a bottle of tincture you will always find a note of the ratio. For example, 1:3 45%. The first number always denotes how much herb has been used in comparison with the second part, which is the liquid. In this case 1 part of herb was macerated in 3 parts of liquid before being filtered out. The liquid is a mixture of alcohol (100% proof sugar beet ethanol) and water. In this case it is 45% alcohol.

Handy Units Calculator Table

ML of dose % alcohol UNITS 
  5 25 0.13
10 25 0.25
  5 35 0.18
10 35 0.35
  5 45 0.23
10 45 0.45
  5 60 0.30
10 60 0.60
  5 90 0.45
10 90 0.90


This should cover most doses and prescriptions.

Calculating units yourself

If you need to calculate units yourself, the formula is:

( Dose in ml x % of alcohol ) divide by 1000 = Units of alcohol

For example 5 x 45 = 125, divide by 1000 = 0.225 which rounded up is 0.23 units of alcohol.

If you drank a 125ml glass of white wine (Chardonnay 12%) you would be consuming 1.5 units of alcohol. If you also had a 5 ml dose of a 1:3 45% herbal tincture you would have consumed 1.5 + 0.23 = 1.73 units of alcohol.

For more about alcohol and herbal tinctures and medicines please click here.

© Napiers Herbals Ltd 2014 • Edinburgh and Glasgow • Herbalists and Medical Botanists since 1860
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