I have a bitch who has been off her food all day and been sick bile but is clearly showing signs of constipation. She is straining and nothing happening but has just passed a small pebble size stool which was hard. I feel so srry for her what can i give her or shall I just go to vets in morning

What does she usually eat?  Did she eat anything at all today?  Is there a chance she has an obstruction?

Mine are raw fed and one dog in particular can get constipated if he has too much bone in one go, this is why I generally like to follow bone with liver.  Alternatively kibble works for him too as it seems to ease the harder material through the digestive system...

Make sure your girl is taking on fluids - add a splash of milk to her water if it helps to encourage drinking, although mine like fresh water straight from the tap.  If water comes back up I'd worry about an obstruction

If you know it's just food then you could take her for a gentle lead walk.  Exercise can really aid peristalsis which is why dogs often get progressively looser poo on a walk.  If she is in pain though, don't wait as the waste material will continue to compact and dry out in the intestine making it more difficult for her to pass.  If you are really worried ring your vet to ask if they can recommend something to give her which will act more quickly or to check her for an obstruction.

Let us know how you get on

Pumpkin works for constipation as well as diarrhoea. Lactulose bought at the chemist[don't tell them it is for the dog] works too, a 5kg dog gets 2mls if that helps re dosage.

We have a few customers cats that suffer from constipation and they come with lactulose and it keeps things moving :) just need to make sure you dont over do it on the quantity you give them.

Be careful she doesn't have a blockage (through having eaten something inedible) - trying to be sick and constipation are classic signs.  If it continues take her to the vet.