Many thanks to those who replied to my posting with explanations of the effect of proteins on the absorption of Sinemet. I'm not sure that this is the whole story . I have had PD for around 12 years and have reached the point where I am very dependent on l-dopa. It is only in the last year or so that milk has caused a severe problem, At best, it seems to take about 40 minutes before a dose of sinemet becomes effective - I assume that this is the time taken for the drug to pass the various barriers between gut and brain. However, cows milk can bring on an 'off' period more quickly than this leading me to think that something in the milk has a more direct action on the brain. Strangely, cheese made with sheep's milk does not produce the same reaction. Perhaps I should experiment with goats milk! I just wondered whether anybody else had noticed the same thing. Nigel Cockle