Jewish Festivals: Medicines
Jewish Festivals: Medicines: When To Take
Medicine generally may not be used on the d'oraita Jewish festival days.

Jewish Festivals: Medicine for Chronic Diseases
You may take medicine on Jewish festivals (whether d'oraita or d'rabanan) for:
  • Chronic diseases, such as Parkinson's disease, or
  • Any disease that affects your entire body.
Jewish Festivals: Medicine for Non-Chronic Diseases
You may take medicine on Jewish festivals for non-chronic illnesses, if skipping one day will prevent cure.  You may not take medicine for non-chronic illnesses if skipping a day will just delay your being cured (unless the disease affects your entire body--in which case, you may take the medicine).

Jewish Festivals: Medicines: When To Take: D'Oraita Festival Days
Here are the d’oraita Jewish festivals:
  • First day of Sukkot, Passover, and Shavuot
  • Seventh day of Passover
  • Shmini Atzeret (8th day of Sukkot)
  • Yom Kippur
  • Both days of Rosh Hashana (even though the second day is d'rabanan).
On these days, as well as on d'rabanan Jewish festivals, you:
  • MUST take medicine whenever there is any question of a life-threatening disease or condition.
  • MAY take medicine for a condition that affects the entire body (illness, weakness, etc.). Consult a rabbi if possible.
    ExceptionYou may not smear substances on skin UNLESS the illness is life-threatening, in which case even smearing is permitted.
  • MAY use some medicines if only part of your body is affected by a non-life-threatening disease--consult a rabbi.
Jewish Festivals: Medicines: When To Take: D'Rabanan Festival Days
You make take medicines for any reason on d’rabanan Jewish festivals--even medicines not allowed on the first day of Jewish festivals--except:
  • Medicines that you smear on skin.
  • If the Jewish festival falls on Shabbat (which can only be second day of Shavuot).
Note The d’rabanan Jewish festivals are the second day of Jewish festivals except Rosh Hashana (actually, the second day of Rosh Hashana IS d’rabanan but has the status of d’oraita), plus the last day of Passover and Simchat Torah outside of Eretz Yisrael.

Jewish Festivals: Squeezing, Dabbing, Smearing
As on Shabbat, you may squeeze a tube of cream on Jewish festivals, but you might not be able to use the cream on the Jewish festival for other reasons—consult a rabbi.
Note Smearing creams or ointments is permitted only in life-threatening situations. Otherwise, you may not smear cream on skin on a Jewish festival (or Shabbat) even using a shinu’i such as using the back of your hand or a toe.
Dabbing is permitted, but only when you are permitted to use medicine. 
Example
You may use cream on a Jewish festival (and Shabbat) by dabbing (you may ONLY dab--you may not SMEAR cream) for a bee sting if it will affect the entire body. You may not use cream for a mosquito bite, since it is only a local irritation.