Hi Mcb
As far as I'm aware, you can take supplements while you are on the Humaworm. I always did. One possible exception is probiotics which are rendered ineffective due the herbs' indiscriminate culling of bacteria.
I'd consider taking any nutritional supplement away from herb ingestion time to give your parasites a dose of poison before they get your expensive vitamins and minerals.
If you are doing your first Liver Flush tonight you should be in good form to commence the Humaworm tomorrow night (the morning will be too soon as you will be too busy with the Epsom salts + butt-pea extravaganza).
I know that Hulda Clarke (who is so very meticulous) suggests completing a parasite cleanse before the Liver Flush... but I, for one, jumbled them up with great results.
All the best