any medicines or some natural way to make my wife crave for sex

Holy Water

Doing chores...being patient with the kids...cooking & cleaning for her. Not asking for sex or hovering around her, especially when you want it.

Hell, I'm not sure any of that really works, but it gets me sex 3-4 times a week and sometimes twice a day if the kids are gone overnight.

I have to agree with erotica88,
If she sees she has more time in the day or she senses that you are helping her, she'll want to reciprocate.
Also take into account women want romance. Do something "different".
Like dressing up to go to a fancy restaurant if you don't normally do that.
Be the dashing James Bond once in awhile rather then blues jeans and t-shirt hubby. I say this generally. This was my case. I look like a lumberjack most of the time. I surprised the wife with reservations at a fancy place and I wore a black suit and tie. She seemed as proud as a peacock strolling into the restaurant.
As soon as we got home after dinner and takes, she dropped to her knees unzipped my pants and started blowing me off as soon as we entered the house. I was STILL in my suit and tie. Who knows, maybe she was playing out some fantasy in her head.

Just my 2 cents

There is a plant with a nickname of Chaste tree, which they used to give to monks to lower their libido, hence the name. Interestingly enough this plant is reputed to have the opposite effect on women.

treat her like a lady....off load her with all duties she has...(if you are not a sissy biy....get a womanmaid to to the house work)...bring flowers home sometimes....tell her several times a day that you love her...buy her tickets to massage studios, SPA, sauna....bring a bottle of champange home sometims...not to get her takes and fuck her, but for her to feel that you care....let her relax and feel good...it will amaze you what effect this will have
A cuck to my GF - A bull to all other women

have a big dick, some experience and an attitude.

testosterone therapy will turn her into a nympho