I Am Suffering From Frequent Diarrhoea Attaccks For Last One

I am suffering from frequent diarrhoea attaccks for last one year. Have taken tratment from different doctors but problem is not permanently cured. All my blood n stool test are ok. They say I am suffering fro I B S(D) I am very careful about my diet also. I tried ayurvedic tratment but no improvement.Pl guide