My pet's gums look white and he seems weak — is that serious?

Go to an emergency vet now. Pale or white gums together with weakness mean the tissues are not getting enough blood or enough red cells, and that means shock, internal bleeding, severe anaemia or a heart problem until proven otherwise. None of those wait until morning.

Check it properly on the way, it takes ten seconds. Lift the lip and look at the gum above one of the big canine teeth in good light. It should be a healthy bubblegum pink and moist. Press it with a fingertip until it blanches white, let go, and count: the colour should flood back in under about two seconds. Slow refill, plus pale gums, plus fast weak breathing is the picture of shock. If your pet has naturally black or spotted gums, look at the inner eyelid or the tongue instead.

Give no food and no water, keep him warm and still, and carry him rather than walk him. When you phone, say the words pale gums and weak — that gets triaged straight to the front. Look at his belly on the way past: in an older, larger dog a belly that seems swollen or feels drum-tight matters, because a bleeding mass on the spleen is a common cause of exactly this picture and it is operable when it is caught in time. Mention any chance of rat bait, a road accident, a fall, or a heart murmur he is known to have, and bring whatever medication he is on.

This is an exam-and-bloodwork emergency. What it actually is gets decided by the tests and by the hands on him, not by a guess from a distance.