Is rennet halal?
Depends on the source
- Usually made from
- Calf stomach or fermentation
- Used as
- enzyme
- Vegan
- Depends on the source
What is rennet?
Rennet is an enzyme preparation, mainly chymosin, that curdles milk in cheesemaking. Traditional rennet is extracted from the fourth stomach of young calves, kids or lambs. Today much of it is made by fermentation with microbes that produce the same enzyme, or comes from moulds (microbial rennet).
Why it's marked “Depends on the source”
Fermentation-made chymosin and microbial rennet come from micro-organisms, so they raise no halal issue. Animal rennet is the question: if it comes from an animal slaughtered the halal way, most accept it, but rennet from pigs or from animals not slaughtered the halal way is where views split. The label rarely says which kind was used.
Where views differ
Scholars differ on rennet from animals that were not slaughtered the halal way. One long-standing view holds that rennet stays pure even then, because it is not considered part of the dead animal in the usual sense; others do not accept it. Rennet from pigs is not accepted. Halal certifiers apply their own rules, so a halal logo shows which view that certifier follows.
How to check the label
Look for “microbial rennet”, “vegetarian rennet”, “non-animal rennet” or a vegetarian mark, or a halal certificate on the cheese. Traditional cheeses with protected names may require animal rennet; ask the maker if the pack doesn't say.
Where you'll find it
- hard and aged cheese
- soft cheese
- cheese in ready meals
- some desserts and junket
Good to know
- US rules define rennet as an extract from the fourth stomach of calves, kids or lambs, and also allow chymosin made by fermentation with a harmless strain of E. coli.
- Labels often just say “enzymes” or “rennet”; vegetarian cheeses use microbial or fermentation-made rennet.
Ingredients people often ask about
See all 89 E-numbers in the halal checker
This list describes where additives usually come from. It isn't a religious ruling, and manufacturers can change their sources. Last reviewed: 14 October 2026.
Sources
Frequently asked questions
Is rennet halal?
Depends on the source. Fermentation-made chymosin and microbial rennet come from micro-organisms, so they raise no halal issue. Animal rennet is the question: if it comes from an animal slaughtered the halal way, most accept it, but rennet from pigs or from animals not slaughtered the halal way is where views split. The label rarely says which kind was used.
What is rennet made from?
Rennet is an enzyme preparation, mainly chymosin, that curdles milk in cheesemaking. Traditional rennet is extracted from the fourth stomach of young calves, kids or lambs. Today much of it is made by fermentation with microbes that produce the same enzyme, or comes from moulds (microbial rennet).
Is rennet vegan?
It depends. Microbial and fermentation-made rennet are vegetarian; traditional rennet comes from calves’ stomachs, so look for a vegetarian or vegan label on cheese.