770 ILCS 5/1
Attorneys at law shall have a lien upon all claims, demands and causes of action, including all claims for unliquidated damages, which may be placed in their hands by their clients for suit or collection, or upon which suit or action has been instituted, for the amount of any fee which may have been agreed upon by and between such attorneys and their clients, or, in the absence of such agreement, for a reasonable fee, for the services of such suits, claims, demands or causes of action, plus costs and expenses. In the case of a claim, demand, or cause of action with respect to which the total amount of all liens under the Health Care Services Lien Act meets or exceeds 40% of the sum paid or due the injured person, the total amount of all liens under this Act shall not exceed 30% of the sum paid or due the injured person. All attorneys shall share proportionate amounts within this statutory limitation. If an appeal is taken by any party to a suit based on the claim or cause of action, however, the attorney's lien shall not be affected or limited by the provisions of this Act.
To enforce such lien, such attorneys shall serve notice in writing, which service may be made by registered or certified mail, upon the party against whom their clients may have such suits, claims or causes of action, claiming such lien and stating therein the interest they have in such suits, claims, demands or causes of action. Such lien shall attach to any verdict, judgment or order entered and to any money or property which may be recovered, on account of such suits, claims, demands or causes of action, from and after the time of service of the notice. On petition filed by such attorneys or their clients any court of competent jurisdiction shall, on not less than 5 days' notice to the adverse party, adjudicate the rights of the parties and enforce the lien.
770 ILCS 5/1