Thanks guys. Very cross with my husband but guess these mistakes can happen , I am not the perfect parent. He's promised to be more careful in future.
Nurse rung back and said not toxic and symptoms to look out for. Ds seems perfectly fine so I think he was playing with them . Got a long lecture about not leaving my son alone and locking away things like that though which made me feel guilty and a bad parent for leaving him alone even though it was dh who left the pills lying around!
If it makes you feel any better I had a similar incident but with rat poison instead of vitamins! Luckily they were blue coloured so I presumed that if DS had eaten any his tongue would be blue, but my heart was in my mouth when I found him in the shed, sitting on the floor with his hand in the box which had a big skull and crossbones on it
XH got a bollocking for that one too, as he was supposed to be keeping an eye on him and had left him alone after getting the poison down from the top shelf (we had just moved onto a farm and it was still there from previous occupants).