There was the apparent poisoning (or was it really just allergic reaction to the food or drink he was ingesting at the time, going by his comments given in a lecture soon after- "all food can become poisonous") on January 1st 1924.
From a couple of letters to Marie Steiner:
"And I have to avoid everything 'destructive'. I can see how easily I can be set back when something disruptive occurs, particularly with regard to the gastric system. "- 15th October 1924
"As you know, I have become very estranged from my physical body since January 1923. That is why an increasing amount of nursing is necessary."
- 26th October 1924
"Wegman and Noll are kept pretty busy with my 'treatment'. I have to suffer a lot with the pain of the treatment and feel how much I am unsuited to spending time on my own care in this way."
"M.d.M., I told you some time ago how, since January 1923, the link between the higher parts of my being and my physical body was no longer complete; living in the spirit I lost, as it were, the immediate connection with my physical organization. Not with the physical world. On the contrary: my ability to make a healthy assessment of the latter grew stronger and also more comprehensive. But precisely because everything in the spiritual realm continued unhindered, also as regards the physical world, the hostile forces are making an assault on my physical body."