Rabbit and iceberg lettuce

Can rabbits eat iceberg lettuce?

Find out why you shouldn't feed iceberg lettuce to your bunny. And is it true that iceberg lettuce has a drug that sends your rabbit to sleep?

Do you have a friend like mine, who turns up their nose if offered a salad to eat? “I don’t eat rabbit food” is their response.

But is everything in a salad good for rabbits?

Many salads contain iceberg lettuce. It adds a bit of crunch to the dish.

But should you feed iceberg lettuce to your bunnies? Is iceberg lettuce rabbit food?

There are a lot of myths on the internet about feeding iceberg lettuce to rabbits – I set out to discover the truth, using scientific journal articles, the experience of owners, and what veterinary experts say.

Here’s what I discovered.

Can rabbits eat iceberg lettuce?

You should not feed iceberg lettuce to rabbits. While rabbits can eat iceberg lettuce in small amounts, the lettuce provides little of nutritional value to bunnies, with low levels of minerals, vitamins and fibre (iceberg lettuce is mostly water). Iceberg lettuce, like many other lettuces, also contains lactucarium, a milky fluid that in large quantities acts on the nervous system, causing sleepiness and reducing pain sensations. In extreme doses, this could lead to diarrhoea or other gut problems, but a few leaves won’t affect your bunny, despite internet myths.

What is the nutritional value of iceberg lettuce?

IngredientAmount per 100g of iceberg lettuce
Calories12 kcal
Fat0 g
Carbohydrate2.35 g
Fibre1.2 g
Sugars1.18 g
Protein1.18 g
Sodium12 mg
Calcium24 mg
Iron0.35 mg
Potassium141 mg
Vitamin D0 mg
Water93.9 g
Sourced from USDA

Iceberg lettuce is mostly water, and is low in minerals, and without significant quantities of any vitamins that rabbits needs.

Iceberg lettuce is also low in fibre, which bunnies need as part of their diet both to keep their teeth in good condition, and also to keep their guts healthy.

In other words, iceberg lettuce provides almost nothing that bunnies need except water.

Iceberg lettuces are not going to keep your rabbit healthy.

Find out more about what rabbits do need in their food in our post here.

What is lactucarium?

Lactucarium is a milky fluid produced by some lettuces, mainly from the stem. It’s a chemical agent that causes both sleepiness and some pain relief (analgesia).

Because it looks a bit like opium, and because of its effects, lactucarium is sometimes called ‘lettuce opium’.

In the past, doctors would prescribe lactucarium as a treatment for insomnia. It was also used as a cough medicine.

What is the effect of lactucarium?

Lactutcarium can cause sleepiness, hallucinations, and pain relief. In wild lettuce (not cultivated iceberg lettuce), you can relatively large amounts.

As an example, eight people in Iran found some wild lettuce and ate loads of it. All of them needed to be admitted to hospital (one to intensive care). Their symptoms included agitation, nausea, dizziness, hallucinations, and blurred vision. All of them recovered fully within 48 hours with no lasting effects. You can read the medical write up here.

This sounds pretty worrying – but wild lettuce and cultivated lettuces like iceberg lettuce are different. Cultivated lettuces don’t have the same levels of lactucarium. And iceberg lettuce isn’t any different from other lettuces you can buy.

You can find many rabbit websites that suggest that romaine lettuce is good for rabbits, but iceberg lettuce is bad because of lactucarium. But romaine lettuce also contains lactucarium. In fact, scientists in Korea used romaine lettuce to extract lactucin and lacucuopricin (compounds found in lactucarium) to see if the chemicals made mice fall asleep more quickly (they did). You can find the study here.

Romaine lettuce is better than iceberg lettuce for rabbits – but it’s nothing to do with lactucarium. Both types of lettuce contain it. Romaine lettuce just has more nutrients – and that’s why it’s a better choice for bunnies.

Peter Rabbit, the Flopsy Bunnies and the effects of lettuce

A hundred years ago, lettuce (not just iceberg – all lettuce) had a reputation for being good for sleep. You can see this in Beatrix Potter’s famous tales.

Here’s an extract from the beginning to the Tale of the Flopsy Bunnies:

It is said that the effect of eating too much lettuce is “soporific.”
I have never felt sleepy after eating lettuces; but then I am not a rabbit.
They certainly had a very soporific effect upon the Flopsy Bunnies!

Illustration of flopsy bunnies eating lettuce leaves.
Image from The Tale of the Flopsy Bunnies, 1909 edition

The flopsy bunnies did stuff flowering lettuces down themselves – which is not a good idea with any food for bunnies except hay.

Should I worry if my rabbit eats some iceberg lettuce?

You do not need to worry if your rabbit eats a few leaves of iceberg lettuce. It will do your rabbit no harm.

If you feed your rabbit large quantities of iceberg lettuce and nothing else, then your bunny may have problems – but not because of lactucarium. It will be because the rabbit has eaten lots of a food that is low in fibre and nutrients and high in water. Not surprisingly, this could cause diarrhoea.

Still worried? One of the foremost vets specialising in rabbits includes lettuce in a list of foods that are safe to buy for your bunny, saying lettuce ‘is not harmful although lettuce is mostly water.’ This vet literally wrote the book about rabbits (US version here).

Conclusion

Rabbits can eat a few leaves of iceberg lettuce safely. However, iceberg lettuce contains so few vitamins, minerals and fibre that it is a poor choice. It won’t do any harm, but neither will it do your bunny much good.

Other posts

If you’re concerned about your rabbit’s diet, check out our post on what nutrients rabbits need.

We also have posts covering what fruit bunnies can eat, and which herbs you can safely give your rabbit.

Want to give your furry friend a treat? Check out our post about cheap toys for bunnies.

Posted by Jonathan