Health / 健康

Anal Glands: What They Are, and Why "Routine Expression" Usually Isn't the Answer

肛門腺（臭腺）とは？「定期的に絞る」が実は推奨されない理由

This one comes up a lot, so let's go through it properly — because the popular advice ("squeeze your dog's anal glands every month") isn't actually what most veterinarians recommend today.

What are anal glands, exactly?

Dogs have two small scent glands on either side of the anus. They produce a strong-smelling fluid, and in a healthy dog, this normally empties on its own during defecation — it's part of how dogs mark territory and identify each other, not a hygiene problem to manage.

Why routine "just in case" expression usually isn't recommended

It's common to hear that anal glands should be expressed on a schedule — monthly at the groomer, for instance. But current veterinary guidance generally advises against expressing healthy, symptom-free glands as a routine habit. Unnecessary manual expression can irritate and inflame the glands, and some vets believe it can actually make the glands more prone to swelling and needing expression again — the opposite of what you're going for. Over-expression can also lead to trauma of the sacs, making infection or abscess more likely rather than less.

In other words: if your dog isn't showing symptoms, there's usually nothing to fix.

The real signs to watch for

Scooting (dragging their bottom along the ground) — occasional scooting isn't necessarily a problem, but repeated scooting over a few days is worth a vet visit
Licking or biting at the area under the tail more than usual
A strong, distinctly fishy odor
Visible swelling, redness, or a wound near the anus

Any of these — especially more than once — is a good reason to call your vet rather than trying to fix it yourself.

Who should actually do the expressing

When a dog does need their glands expressed (because of impaction, not as prevention), it's best done by a vet or an experienced groomer working under their guidance. Internal expression, done properly, is more effective and less irritating than external squeezing, and a vet can also check for infection or abscess while they're at it — something you can't diagnose by yourself.

What actually helps, day to day

A diet that produces firm, well-formed stool helps glands empty naturally during defecation — talk to your vet if your dog's stool is often soft
Keeping your dog at a healthy weight (see our nutrition guide) — very overweight dogs sometimes have more trouble with natural gland expression
If your dog has recurring gland issues, ask your vet about underlying causes (allergies and low-grade skin issues are common contributors) rather than treating it as a purely mechanical problem

The short version: watch for the real signs, and let a vet be the one who decides whether expression is actually needed.

Sources:

この話題はよく聞かれるので、きちんと整理しておきます。「毎月肛門腺を絞りましょう」というのはよく聞くアドバイスですが、実は現在の獣医療で一般的に推奨されている方法ではありません。

肛門腺とは何か

犬には肛門の両脇に小さな分泌腺（肛門腺・臭腺）が2つあります。ここから強い匂いのある分泌液が作られ、健康な犬であれば通常は排便のたびに自然と排出されます。これは衛生上の問題というより、犬同士がお互いを識別したり縄張りを示したりするための仕組みです。

「念のため」の定期的な圧出がすすめられない理由

「トリミングのたびに毎月絞りましょう」という話はよく耳にしますが、現在の獣医師の一般的な見解では、症状のない健康な肛門腺を習慣的に絞ることは推奨されていません。不要な圧出は腺を刺激し炎症を起こすことがあり、かえって腫れやすくなって「またすぐ絞る必要がある」という悪循環を招くと考える獣医師も少なくありません。狙いとは逆の結果になってしまうのです。過度な圧出は嚢（のう）を傷つけ、感染や膿瘍のリスクをむしろ高める可能性もあります。

言い換えると、症状が出ていないなら、基本的に「直すべきこと」自体がない、ということです。

本当に注意すべきサイン

床にお尻を擦りつける「そり歩き」— 1回だけなら必ずしも問題ではありませんが、数日にわたって繰り返す場合は受診の目安です
尻尾の下あたりを普段より頻繁に舐める・噛む
強い、はっきりとした生臭いにおい
肛門周辺の腫れ、赤み、傷が見える

これらのサイン、特に一度きりでなく繰り返す場合は、自己判断で対処しようとせず動物病院に相談するのが一番です。

実際に絞る必要がある時は誰が行うべきか

（予防としてではなく）詰まりなどで実際に処置が必要な場合は、獣医師、またはその指導のもとで経験豊富なトリマーが行うのが望ましい方法です。正しい手技での内部からの圧出は、外部から押すよりも効果的で刺激も少なく、獣医師であれば同時に感染や膿瘍の有無も確認できます。これは自分で診断できることではありません。