Do show sympathy
Morning sickness can be really rough. It's not her fault, so be nice. Get a damp cloth for her forehead, tell her it won't last long and everything will be OK. This is what she wants to hear, and has the advantage of being true too.
Don't panic
And don't let her panic about not keeping enough food down. If she really can't keep anything at all down, especially water, call the doctor immediately, but the vast majority of women will get enough nourishment for themselves and the baby from whatever they can eat and drink.
Do get her whatever she asks to eat
Morning sickness can coincide with hormone-induced cravings for strange foods. She might also want to try anything her friends or family suggest as remedies for the sickness, from sour sweets to cold toast, and at any time of day or night. By the end of the first three months you will be on first name terms with every member of staff at the local all night garage.
Don't eat smelly foods
At least not in front of her. The smells of some hot foods can trigger vomiting. So don't come home and plonk yourself down on the sofa with a curry or some kippers.
Do get cooking
Again, smells might set her off, so let her sit down with a magazine or the telly while you rustle something up. Remember, nothing spicy or too sweet. Better still, make cold meals that are low fat, high carb. Stuff like toast, pasta, crackers and crispbread are good, so you don't have to be Gordon Ramsay. Luckily for her.
Don't cook big meals
She should try to eat little and often. Same goes for drinking - make sure she has a glass of water near her all the time.
Do give her breakfast in bed
Apparently a couple of Rich Tea or some dry toast before getting up can work wonders. They can help boost her blood sugar levels and ease the early morning nausea.
Don't go (ginger) nuts
Although it's often been mentioned as a cure for morning sickness there's no evidence that it works and because ginger products are unregulated there's no research on possible side effects. So no need to snap up everything sold in Holland and Barrett. Try offering her some ginger biscuits, cake or even a gingerbread man, some mums claim these can help plus they taste nice so if they don't work at least you know they won't go to waste!
Do talk to the GP
If none of this is working call the doctor. In some cases they may give her a short course of anti-vomiting drugs that are safe to take during pregnancy.