A pilgrim is permitted to do the following things while in a state of ihram:
1. Taking a Bath and Changing Clothes
2. Covering the Face to keep out dust
3. Wearing Shoes (for Women)
4. Covering the Head by Mistake
5. Cupping, Opening an Abscess, Pulling a Tooth or Cutting a Vein
6. Scratching the Head and Body
7. Looking in the Mirror and Smelling Sweet Basil
8. Wearing a Money Belt on the Waist and Wearing a Ring
9. Wearing Kohl
10. Sitting in the Shade of an Umbrella, a Tent, a Roof, etc.
11. Using Henna
12. Killing Flies, Fleas, and Lice
13. Killing the Five Vicious Animals and Others that are Harmful

Sheikh Sayyed Sabiq states in his well known book Fiqh As-Sunnah:

1. Taking a Bath and Changing Clothes

Ibrahim An-Nakh`i said: “Whenever our companions approached the well of Maymun, they would take a bath and then put on their best clothes.” It is said that Ibn `Abbas entered a public bath at Al-Juhfah (to take a bath), while he was in the state of ihram. He was asked: “How do you do so while in the state of ihram?” He replied: “Allah does not need any of our dirt and filth!”

Using soap or any other cleaning agent is permissible. Ash-Shafi`i and Hanbali schools hold that one may use perfumed soap for bathing, and similarly women are permitted to undo their hair and comb it, because the Prophet (peace and blessings be upon him) ordered `A’ishah, saying, “Undo your hair and comb it.” (Muslim)

2. Covering the Face to keep out dust

Ash-Shafi`i and Sa`id ibn Mansur reported from Al-Qasim that he said: “`Uthman ibn `Affan, Zayd ibn Thabit, and Marwan ibn Al-Hakam used to cover their faces while in the state of ihram.”

3. Wearing Shoes (for Women)

Abu Dawud and Ash-Shafi`i reported on the authority of `A’ishah that Allah’s Messenger (peace and blessings be upon him) permitted women to wear their shoes while in the state of ihram. Men, however, must wear sandals that do not cover the heel.

4. Covering the Head by Mistake

The Shafi`i school holds that there is no harm if a pilgrim forgot and covered his head or wore a shirt in a state of forgetfulness. `Ata’ said: “There is no blame on such a person, but he should seek forgiveness of Allah.” The Hanafi school says that such a person will have to redeem himself (by offering a sacrifice).

5. Cupping, Opening an Abscess, pulling a Tooth or Cutting a Vein

It is verified that Allah’s Messenger cupped himself in the middle of his head while he was in a state of ihram. Malik said: “There is no blame upon a muhrim (one in the state of ihram) if, in case of need, he opens an abscess, wraps a wound, or severs a vein.” Ibn `Abbas said: “A person in the state of ihram may pull his tooth or open an abscess.”

6. Scratching the Head and Body

`A’ishah was asked about a pilgrim whose body was itching. She said: “Yes, he or she may scratch as strongly as he or she likes.”

7. Looking in the Mirror and Smelling Sweet Basil

Ibn `Abbas said: “A person in a state of ihram is permitted to smell sweet basil, look in a mirror, and cure himself by eating butter and oils.” `Umar ibn `Abdul `Aziz used to look in the mirror and use the tooth stick (siwak) while in a state of ihram.

8. Wearing a Money Belt on the Waist and Wearing a Ring

Ibn `Abbas said: There is no harm if a muhrim wears a ring or a money belt to keep his money.

9. Wearing Kohl

Ibn `Abbas said: A person in a state of ihram may wear kohl if his or her eyes are sore, provided the kohl is not perfumed. There is consensus among scholars on its permissibility for treatment but not as a means for beautification.

10. Sitting in the Shade of an Umbrella, a Tent, a Roof, etc.

`Abdullah ibn `Amer reported: `Umar used to throw a piece of leather on a tree and sit under its shade while he was in the state of ihram. This is reported by Ibn Abi Shaiba.

11. Using Henna

The Hanbali school holds that it is not forbidden for a muhrim, male or female, to use henna to dye any part of the body, except the head. The Shafi`i school holds that a male muhrim may use henna to dye any part of the body except hands and feet, the dying of which without any genuine cause is not permissible while in the state of ihram. Also, covering one’s head with thick (layers of) henna is not permissible. They also hold that it is not desirable for a woman in the state of ihram to use henna, and that it is unlawful for her to do so if she is in `iddah after the death of her husband.

The Hanafi and the Maliki schools, on the other hand, hold that a muhrim, male or a female, is not permitted to use henna to dye any part of the body because it is a perfume, and a muhrim is not allowed to wear perfume while in the state of ihram.

12. Killing Flies, Fleas, and Lice

`Ata’ was asked by a man about the fleas or ants that vexed him while he was in the state of ihram. He replied: “You may throw away what does not belong to you.” Ibn `Abbas said: “A muhrim may kill lice and ticks.”

13. Killing the Five Vicious Animals and Others that are Harmful

`A’ishah reported that the Prophet (peace and blessings be upon him) said: “Five of the animals are vicious and they may be killed in the sacred precincts of Al-Haram: the crow, the kite, the scorpion, the mouse, and the ravenous dog. This is reported by Muslim and Al-Bukhari, who added “…(and) the snake.”