The Decision of the National Fatwa
The 88th National Fatwa Council Committee for Islamic Religious Affairs Malaysia at its meeting on October 2, 2009 had discussed the Usage of Patterned Henna according to Syarak and decided that:

1. Application of henna on hands and feet is harus for women, whether married or not as long as it does not lead to slander.
2. However, the application of henna on both hands and feet are limited to the wrists and ankles, whereas the colours used are not permanent like tattoo and contain no element of doubt. On the pattern and design used, patterns or designs of leaves and plants is allowed, while that of animals, symbols of gods or religion or any appearance that is in conflict with the Islamic law is strictly prohibited.
3. The usage of henna on the hands and feet of a man is not harus except on several fingers for the groom during the wedding ceremony and also for medicinal purposes.

Summary
The Perak Mufti Department adopted the view issued by the National Fatwa Council Committee for Islamic Religious Affairs Malaysia at its 88th meeting on 2nd October 2009 with recommendations that any party needs to stop doing things that is vague in hukum to something that is definite in hukum.

Meaning: "Abu Muhammad al-Hasan bin Ali bin Abi Talib, the Prophet SAW’s favourite grandson, he said: I memorized from the Prophet SAW(saying): Leave that which is doubted to something that you don’t doubt."

Question:
I put the dye my fingers, then perform ablution(wuduk) and pray(solat) without removing it first. Is my prayer is valid?

Answer:
The solat is batal, because the usage of colouring during solat is not harus, the colouring prevents the water from reaching the skin during ablution. Anything that prevents water from reaching the skin, should not be used for ablution or bath, because Allah SWT says:

Meaning: "O you who believe! When you prepare for Solat, then wash your faces and your hands including up to the elbows and wipe your heads and wash your feet up to the ankles…" (Al-Maidah: 6)

The Hukum of Using Henna For Medication

Question:
Lajnah Daa'imah Lil Ifta 'asked: What is the hukum on using henna on the hair for the purpose of treating hair loss, it is not to change the hair colour?

Answer::
It is allowed.