<SEC-DOCUMENT>0001209191-21-036240.txt : 20210527
<SEC-HEADER>0001209191-21-036240.hdr.sgml : 20210527
<ACCEPTANCE-DATETIME>20210527161713
ACCESSION NUMBER:		0001209191-21-036240
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20210525
FILED AS OF DATE:		20210527
DATE AS OF CHANGE:		20210527

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Lenk Robert P
		CENTRAL INDEX KEY:			0001362635

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-34375
		FILM NUMBER:		21972910

	MAIL ADDRESS:	
		STREET 1:		LUNA INNOVATIONS INCORPORATED
		STREET 2:		2851 COMMERCE STREET
		CITY:			BLACKSBURG
		STATE:			VA
		ZIP:			24060

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			PLUS THERAPEUTICS, INC.
		CENTRAL INDEX KEY:			0001095981
		STANDARD INDUSTRIAL CLASSIFICATION:	SURGICAL & MEDICAL INSTRUMENTS & APPARATUS [3841]
		IRS NUMBER:				330827593
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		4200 MARATHON BLVD.
		STREET 2:		SUITE 200
		CITY:			AUSTIN
		STATE:			TX
		ZIP:			78756
		BUSINESS PHONE:		737.255.7194

	MAIL ADDRESS:	
		STREET 1:		4200 MARATHON BLVD.
		STREET 2:		SUITE 200
		CITY:			AUSTIN
		STATE:			TX
		ZIP:			78756

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	CYTORI THERAPEUTICS, INC.
		DATE OF NAME CHANGE:	20050712

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	MACROPORE INC
		DATE OF NAME CHANGE:	20010320
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc4.xml
<DESCRIPTION>FORM 4 SUBMISSION
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2021-05-25</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001095981</issuerCik>
        <issuerName>PLUS THERAPEUTICS, INC.</issuerName>
        <issuerTradingSymbol>PSTV</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001362635</rptOwnerCik>
            <rptOwnerName>Lenk Robert P</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O PLUS THERAPEUTICS INC.</rptOwnerStreet1>
            <rptOwnerStreet2>4200 MARATHON BOULEVARD, SUITE 200</rptOwnerStreet2>
            <rptOwnerCity>AUSTIN</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>78756</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Option (Right to Buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>2.25</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2021-05-25</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>6336</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <value>2031-05-25</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>6336</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>6336</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The options vest monthly over 12 months from the Grant Date in substantially equal monthly installments, provided that the options vest in full on the Issuer's next regularly scheduled annual meeting of stockholders that occurs following the Grant Date, subject to the Reporting Person's continued service to the Issuer through each applicable vesting date or, if earlier, such annual meeting.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Andrew Sims, attorney-in-fact</signatureName>
        <signatureDate>2021-05-27</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
