Inhaler is vaporized and does not reach the stomach, so in that case, we say that there is no objection to using it when you are fasting, and it will not cause you to break your fast, because as we have said, none of its particles enter the stomach. Since it is something that is defused and vaporized, and it disappears, then none of it reaches the stomach, therefore it is permissible for you to use it when you are fasting and the fast is not invalidated by it.
Shaykh Muhammad bin Saalih al-`Uthaymeen
Fatawa Arkaanul-Islaam, DARUSSALAM, Vol.2, p.658
If the swimmer thinks it most likely that no water will enter his stomach through the mouth or nose, and he is a good swimmer and can guarantee that his fast will not be broken, then in that case there is nothing wrong with him swimming.
The ruling is the same as that on doing ghusl when fasting. The scholars have stated that that is permissible even if it is just for the purpose of cooling down.
A man may kiss, embrace and touch his wife, without having intercourse, when he is fasting. This is permissible and there is nothing wrong with it, because the Prophet (peace and blessings of Allaah be upon him) used to kiss and touch his wives when he was fasting. But if there is the fear that he may do something that Allaah has forbidden because his desire is aroused quickly, then it is makrooh for him to do that. If he ejaculates he still should not eat or drink for the rest of the day, and he has to make up the fast, but he does not have to offer kafaarah (expiation) according to the majority of the scholars. But madhiy (prostatic fluid) does not invalidate the fast, according to the more correct of the two scholarly views, because the basic principle is that the fast remains valid, and because it is too difficult to avoid. And Allaah is the Source of strength.
Fataawa al-Shaykh Ibn Baaz, part 4, p. 202
it is permissible for the fasting person to put it on at the beginning of the day and at the end, whether the perfume is in the form of incense, oil or whatever, but it is not permissible to inhale incense because incense contains particles which, if inhaled, may reach the stomach through the nose.
Hence the Prophet (peace and blessings of Allaah be upon him) said to Laqeet ibn Sabrah: “Rinse your nose thoroughly, unless you are fasting.”
Fataawa Arkaan al-Islam, p. 46.
It says in Fataawa al-Lajnah al-Daa’imah (10/252):
It is permissible to be given medicine via injection into the muscles or veins when fasting during the day in Ramadan.
But it is not permissible for the fasting person to be given nutrients during the day in Ramadan, because that comes under the same rulings as consuming food and drink, and this injection is regarded as a means of breaking the fast in Ramadan. If it is possible to give the injection into a muscle or vein during the night, that is preferable.
Shaykh Ibn ‘Uthaymeen said:
Shaykh al-Islam Ibn Taymiyah was of the view that kohl does not break the fast, not even if the taste of the kohl reaches the throat. He said, this is not called food or drink, and it is not like food or drink, and it does not have the same effect as food or drink. There is no saheeh hadeeth from the Prophet (peace and blessings of Allaah be upon him) which expressly indicates that kohl breaks the fast, and the basic principle is that it does not break the fast.
Shaykh Ibn ‘Uthaymeen said in Fataawa Ramadaan (p. 511):
If nose drops reach the stomach or the throat, then they break the fast,
because the Prophet (peace and blessings of Allaah be upon him) said, according to the hadeeth of Laqeet ibn Sabrah: “Snuff water up into the nose deeply, unless you are fasting.”
So it is not permissible for the fasting person to put drops in his nose that can reach his stomach or his throat, but as for nose drops that will not reach them, they do not break the fast.
Shaykh Ibn ‘Uthaymeen was asked in Fataawa Arkaan al-Islam, p. 478, about the ruling on a fasting person having a blood test, and whether that breaks the fast.
The fasting person does not break the fast by having blood taken for a test. If the doctor needs to take blood from the patient to test it, this does not break the fast, because it is a small amount of blood and it does not affect the body in the way that cupping does. The basic principle is that the fast remains valid and cannot be spoiled except by things for which there is shar’i evidence that they affect the fast. In this case there is no evidence that the fasting person breaks his fast because of this small amount of blood. With regard to taking a large amount of blood from a fasting person in order to donate it to a person who needs it, for example, then if a large amount of blood is taken which has the same effect on the body as cupping, this does break the fast. Based on this, if the fast is obligatory then it is not permissible for anyone to donate a large amount of blood to anyone, unless the person who is to receive that blood is in dire need and cannot wait until after the sun sets, and the doctors have decided that the blood of this fasting person will benefit him and will meet his immediate need for it.
In this case there is nothing wrong with donating blood, and he may break his fast and eat and drink in order to regain his strength, and he should make up this day when he broke his fast.
narrated by al-Tirmidhi (720) from Abu Hurayrah (may Allaah be pleased with him), that the Prophet (peace and blessings of Allaah be upon him) said: “The one who cannot help vomiting does not have to make up the fast, but the one who vomits deliberately has to make it up.” Classed as saheeh by al-Albaani in Saheeh al-Tirmidhi.
Praise be to Allaah.
All kinds of preparations that are put on the outside of the body, whether they are absorbed through the skin or not, and whether they are for treatment, moisturizing, beautification or any other purpose, do not break the fast unless they are swallowed by the fasting person.
The mere fact that it has a taste does not affect the fast so long as one does not swallow anything.
Shaykh Ibn Baaz (may Allaah have mercy on him) was asked in Majmoo’ al-Fataawa (15/260)
It is permitted, but it is preferable not to use them because the toothpaste is too strong and may go down into the throat. Instead of doing that during the day, one should do it at night.
Al-Sharh al-Mumti’ by Ibn ‘Uthaymeen, 6/407, 408
“If a man experiences a wet dream this does not invalidate his fast, because it was involuntary on his part; it is similar to the case when something enters his throat whilst he is sleeping.”
See al-Mughni by Ibn Qudaamah, vol. 3, p. 22
If the blood reaches the stomach without any deliberate action on the part of the fasting person, it does not break his fast, because Allaah says (interpretation of the meaning):
“Allaah burdens not a person beyond his scope. He gets reward for that (good) which he has earned, and he is punished for that (evil) which he has earned. ‘Our Lord! Punish us not if we forget or fall into error’”
And it says in the hadeeth that Allaah said, “I have done that”, i.e., I have forgiven you.
But if it is possible to prevent it, or to spit it out, and you do not do so and you swallow it deliberately, then this breaks the fast. The evidence for that is the words of the Prophet (peace and blessings of Allaah be upon him) to Laqeet ibn Sabrah: “Go to extremes when rinsing your nose, unless you are fasting.” (Narrated by Abu Dawood, 2366; al-Tirmidhi, 788; al-Nasaa’i, 87; Ibn Maajah, 407. Classed as saheeh by al-Albaani in Saheeh al-Tirmidhi, 631)
Shaykh Ibn ‘Uthaymeen was asked in Fataawa al-Siyaam (p. 356):
Is the fast invalidated by tasting food?
He replied: The fast is not invalidated by tasting food so long as one does not swallow it, but you should not do that unless there is a need for it; in that case if a little of it reaches your stomach by accident your fast is not invalidated.