Jaggery should be old, atleast one year before usage

What is jaggery? How to prepare it?It is a type of unrefined sugar, prepared from sugarcane or date juice. The juice is concentrated by heating and molasses is not removed while concentrating it. The end product is brownish yellow coloured solid jaggery blocks. It is also available in semisolid form.

Jaggery is called as Guda, Gud, Gula, Gulam in Ayurveda. Ayurveda explains two types of jaggery.
Dhauta – washed / semi-refined
Adhauta – unrefined, unwashed.

Qualities of jaggery and health benefits: 

(Reference: Ashtanga Hrudayam Sutrasthana 5/47-48)

Guda (jaggery, molasses), washed well (made white and purified)-
Natishleshma kara – does not increase Kapha to a large extent
Srushtamutrashakrut – increases volume of urine and faeces

If it is not prepared properly, it causes intestinal worms, increases chances of Kapha disorder in marrow, blood, fat tissue and muscles.
Old jaggery is good for heart, and should be consumed. So, jaggery should be at least one year old for its usage.
Freshly prepared jaggery increases Kapha and causes indigestion. 47-48.

unrefined or unwashed jaggery is
Sakshara – slightly alkaline
Natisheeta – not very coolant
Snigdha – oily, unctuous
Mutrashodhaka – cleanses bladder and urine
Raktashodhaka – cleanses and purifies bloodVataghna – balances Vata
Na ati pittajit – decreases Pitta slightly
Medakara – increases body fat
Kurmikara – causes intestinal worm infestation
Balya – increases strength
Vrushya – aphrodisiac

Jaggery for splenomegaly:For the treatment of splenomegaly (Plihodara), Haritaki – Terminalia chebula, in a dose of 3 – 5 grams once or twice a day, is administered along with  2- 3 grams of jaggery. (Charaka Samhita Chikitsa Sthana 13)

Dhauta guda or washed jaggery isMadhura – sweet
Vatapittaghna – balances Vata and Pitta
Asruk prasadana – cleanses and detoxifies blood
It has a more Pitta balancing action compared to Adhauta (unwashed)

Purana Guda – old jaggery:Svadutara – much more sweeter than the fresh
Snigdha – oily, unctuous
Laghu – lighter to digest, than fresh
Agnideepana – promotes digestion strength
Vitshodhaka – cleanses intestines and feaces
Mutrashodhaka- cleanses urinary bladder and urine
Amashayashodhaka – cleanses stomach
Ruchya – promotes taste
Hrudya – good for heart, cardiac tonic
Pittaghna – balances Pitta
Vataghna – balances Vata
Tridoshaghna – Generally good for all the three Doshas
Jwarahara – Good for fever (in small quantities only)
Santapa shantiprada – releives excess body heat
Shramahara- releives tiredness
Panduhara – useful in anemia
Pramehantaka- useful in urinary tract diseases

प्रभूतक्रिमिमज्जासृङ्मेदोमांसकरो गुडः||२३८||
क्षुद्रो गुडश्चतुर्भागत्रिभागार्धावशेषितः|
रसो गुरुर्यथापूर्वं धौतः स्वल्पमलो गुडः||२३९||
ततो मत्स्यण्डिकाखण्डशर्करा विमलाः परम्|
यथा यथैषां वैमल्यं भवेच्छैत्यं तथा तथा||२४०||
वृष्या क्षीणक्षतहिता सस्नेहा गुडशर्करा|
कषायमधुरा शीता सतिक्ता यासशर्करा||२४१||
रूक्षा वम्यतिसारघ्नी च्छेदनी मधुशर्करा|
तृष्णासृक्पित्तदाहेषु प्रशस्ताः सर्वशर्कराः||२४२||
prabhūtakrimimajjāsṛṅmedomāṃsakaro guḍaḥ||238||
kṣudro guḍaścaturbhāgatribhāgārdhāvaśeṣitaḥ|
raso gururyathāpūrvaṃ dhautaḥ svalpamalo guḍaḥ||239||
tato matsyaṇḍikākhaṇḍaśarkarā vimalāḥ param|
yathā yathaiṣāṃ vaimalyaṃ bhavecchaityaṃ tathā tathā||240||
vṛṣyā kṣīṇakṣatahitā sasnehā guḍaśarkarā|
kaṣāyamadhurā śītā satiktā yāsaśarkarā||241||
rūkṣā vamyatisāraghnī cchedanī madhuśarkarā|
tṛṣṇāsṛkpittadāheṣu praśastāḥ sarvaśarkarāḥ||242|| – Charaka Samhita Sutrasthana 27

Treacle / jaggery (Guda) causes increased parasitic infection.
Majjakara – It increases the quantity of marrow,
Asruk kara – improves blood,
medo Mamsakara – increases fat and muscles.
Before its formation as treacle (guda) the sugar cane juice undergoes four stages viz.
Ardhavasheshita ( when only ½ of the juice remains in the process of boiling),
Tribhaga avaseshishita (when 1/3 rd remains),
Chaturbhag Avasheshita (when ¼ th remains) and
Kshudra Guda or Phanita (Inspissated juice black in color).
The juice undergoing transformation through all these four stages is progressively heaviest.
That is to say the Phanita (inspissated juicepnidium) is the heaviest.

Precautions and side effects:Long term use, in high dose may cause weight gain.
Not recommended in diabetes.
Jaggery use, continuously for a long period of time may cause intestinal worm infestation.
Jaggery is contra indicated if you have ulcerative colitis.
Taking radish and jaggery along with fish is contra indicated in Ayurveda.
In case of Shotha – swelling, inflammation disorders, taking jaggery products is contra indicated.

Is there any benefit of using jaggery in diabetes?Jaggery contains sugar hence is not recommended in diabetes. However, the amount of sugar per gram of jaggery is lesser than that of one gram of white sugar. Hence, if your diabetes is under good control and if you are using sugar in your diet (say, in coffee or tea), it is best for you to replace white sugar with jaggery.

Unique use of jaggery in intestinal worms:Jaggery – if used for long time may cause intestinal worms. But in some Ayurvedic medicines, used in treating intestinal worm infestation, like Manibhadra Guda, jaggery is used as ingredient. This will help in attracting the worms into the intestines and to kill them with the other herbs in the medicine.

(My note: The theory about jaggery causing intestinal worms seems to be based on usage over very long time.)

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