Exhibit 5.1 Opinion re: legality [Letterhead of Joel Seidner, Esq.] December 12, 2005 Edward Alexander, Chief Executive Officer PROTON LABORATORIES, INC. 1135 Atlantic Avenue, Suite 101 Alameda, CA 94501 Dear Mr. Alexander: As counsel for PROTON LABORATORIES, INC., a State of Washington corporation (the "Company"), you have requested me to render this opinion in connection with the Registration Statement of the Company on Form SB-2 ("Registration Statement") under the Securities Act of 1933, as amended (the "Securities Act"), filed with the Securities and Exchange Commission relating to the resale of 50,000,000 shares of common stock, par value $.0001 per share (the "Common Stock") by certain security holders of the Company who are listed as the Selling Stockholders in the Registration Statement. I am familiar with the Registration Statement and the registration contemplated thereby. In giving this opinion, I have reviewed the Registration Statement and such other documents and certificates of public officials and of officers and directors of the Company with respect to the accuracy of the factual matters contained therein as I have felt necessary or appropriate in order to render the opinions expressed herein. In making my examination, I have assumed the genuineness of all signatures, the authenticity of all documents presented to us as originals, the conformity to original documents of all documents presented to us as copies thereof, and the authenticity of the original documents from which any such copies were made, which assumptions I have not independently verified. Based upon the foregoing, I am of the opinion that: 1. The Company is a corporation duly organized, validly existing and in good standing under the laws of the State of Washington. 2. The shares of Common Stock underlying the equity line of credit, at such time as common stock is put to the selling stockholder according to the terms of the equity line of credit, will be validly issued, fully paid and nonassessable. I consent to the use in the Registration Statement of the reference to Joel Seidner, Esq. as an expert under the heading " INTEREST OF NAMED EXPERTS AND COUNSEL." This opinion is conditioned upon the Registration Statement being declared effective by the Securities and Exchange Commission and upon compliance by the Company with all applicable provisions of the Securities Act and such state securities rules, regulations and laws as may be applicable. Very truly yours, /s/ Joel Seidner, Esq.