Tell her to STOP using The Master Cleanse NOW!!!! Not all cleanses are safe for all people and this is definatly one of the more risky ones because it includes a salt water prep. She is getting signs form her body to stop and she needs to, there are many other cleanses out there that are much safer! I have read many peoples acounts of reacting badly to the salt cleanse - not good.
Her body is trying to tell her this is not good for her. She may have an electrolite imbalance as a result of this cleanse and should take it really easy for a while. Stay away from salt. Good fruits and veggies are a nice place to start. If she goes to co-ops, they have packets of electrolight powders which may help, or gatorade. But if she eats potassium (like from potatoes and banannas), magnisium and calcium from foods this should help to balance the salt. Lemon juice in plain water 20 min to 1 hr before food can be a gental way of cleaning the liver.
Again tell her to stop the cleanse and if she is still reacting to see a doctor, salt reactions are nothing to mess around with. If she has any previous heart conditions she really needs to see a doc and stay away from salt.