We reconstituted functional follicles from isolated cells, after embedding in a collagen matrix. Therefore we could carry out many investigations. We showed that the cells embedded in collagen reorganized into functional follicles secreting thyroglobulin (Tg) visualised in the intra-follicular compartment, and triiodothyronine (T3) after TSH stimulation. We used these reconstituted follicles for testing several drugs, amiodarone, propranolol and some anaesthetic drugs (thiopental, midazolam and ketamine). We observed that all these drugs inhibited partially or totally, according to the dose administered, the follicular production of Tg and T3. We also found that the follicles reconstituted from thyroid Grave's tissues gave an abnormal secretion of Tg and T3. Finally we created in Rennes a human thyroid model that permits the exploration of pathologic tissues and that may be used in pharmacotoxicology.